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| ISBN-13: | 9780486166032 |
|---|---|
| Publisher: | Dover Publications |
| Publication date: | 03/21/2013 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| Pages: | 207 |
| File size: | 15 MB |
| Note: | This product may take a few minutes to download. |
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Seashore Life of Florida and the Caribbean
By Gilbert L. Voss
Dover Publications, Inc.
Copyright © 1980 Gilbert L. VossAll rights reserved.
ISBN: 978-0-486-16603-2
CHAPTER 1
Collecting and Preservation
Undoubtedly, one of the main reasons why shell collecting is so popular is the ease with which the day's take can be cleaned and preserved. A few minutes of boiling suffices to loosen the animal; it can be removed and discarded and, voilà! the specimen is ready to be identified, labeled, and relegated to the cabinet. With most of the other invertebrates, however, the problems are much greater.
In the first place, collecting is more of a problem. Most of the animals described in this book are somewhat secretive, burrowing into mud, sand, or even rock thus requiring much digging or hammering to pry them out, or they may retreat into algal mats or coral rubble from which they can be extracted only with much effort. Others sting or pinch and some are very swift runners, such as the crab Sally Lightfoot. Thus the collector may need to go into the field armed not only with pail and screw-top jars, but with rock hammer, stout-bladed knife, dip net, and shovel. A small beach seine and a push net are valuable assets.
Equipped with these tools (and a friend to carry them), a discerning eye, and an inquisitive mind, a wide diversity of invertebrates will become your captives. Here another problem arises! What do you do with them? My advice is to keep the specimens in a jar or bucket of seawater, watch them, observe their movements and colors, perhaps identify them without ruining your book by getting it soaked with salt water, and finally turn them loose to go their ways back to their homes.
If closer examination is required, the collection should be sorted out to be sure that only those desired are retained, duplicates and unwanted specimens returned to the sea, and only the remainder taken home. These specimens are best studied either by keeping them alive in an aquarium, examining them fresh in seawater in a white porcelain pan, or by preserving them permanently either dried or in one of the liquid preservatives.
Many of the animals described and illustrated in this book make excellent aquarium residents. Care must be exercised that only compatible animals are kept together; many rare specimens otherwise may disappear during the night, eaten by one of the other inhabitants. Only experimentation will reveal the proper food to be used and the compatibility of the specimens. Some animals, for example, corals and alcyonarians, are very difficult to maintain without special aquarium set-ups.
Because of the great variety of types of animals included in this guide, various methods of preservation are needed. Some hard-shelled types may be dried; soft-bodied animals almost always require liquid preservation. Sea anemones and others are strongly retractile and unless narcotized will draw up into a fleshy glob if placed directly in preservative.
The most commonly accessible narcotizing agent is Epsom salts. The animal to be narcotized is placed in a clean glass or porcelain tray or dish (contact with bare metal will cause most animals to contract), covered with salt water, and allowed to expand fully. Then either crystals of Epsom salts or a saturated solution in seawater is slowly introduced into the dish until the animal gives no response when touched. It is then killed by very slowly introducing either alcohol or formalin until the animal is dead. It is then fixed in the proper preservative and transferred to an appropriate-sized jar and labeled.
Three major types of preservatives are used: formalin, ethyl alcohol, and isopropyl alcohol. Formalin is a saturated solution of formaldehyde gas in water. When purchased over the counter at a drugstore, U.S.P formaldehyde is a 38 to 40% solution of formaldehyde gas in water but is 100% formalin. To make a 10% solution—as is most often used for preservation—mix one part of U.S.P commercial formaldehyde with nine parts of water. The fumes are strong, so formaldehyde should not be used extensively in a closed room.
Two types of alcohol may be used; ethyl and isopropyl. Ethyl alcohol (ethanol) is preferred in museums and is used at 70% with freshwater. It is expensive. Although 70% ethanol is recommended, isopropyl alcohol is comparatively inexpensive and has the added attraction that it is used at 40% solution, so much less is required. It may have some deleterious effects upon some specimens, but it is becoming more popular even in the big museum collections.
Because of the varying consistency, fragility, chemical composition, contractability, and other characters of invertebrates, a variety of different methods are used in their preservation. The following preservative methods will be found useful for most purposes.
Sponges will rot and give off strong odors if they are not properly preserved. Specimens should be preserved in either 70% ethanol or 40% isopropyl alcohol. They may later be dried or retained in the preservative.
Jellyfishes are best preserved in either 5 or 10% formalin. Corals should be killed in freshwater and the flesh allowed to rot. It can then be washed away with a water jet and the skeleton dried and bleached in the sun. Sea anemones are difficult to expand and preserve, and their colors soon fade away. If one is determined to try, the anemone should be placed in seawater in a dean glass or china dish or bowl and left to expand. It may then be narcotized with Epsom salts and finally killed and fixed by the gradual introduction of formalin. At the last moment it may still contract and all the work will be in vain. If you are successful, final preservation is in 10% formalin. Alcyonarians may simply be dried in the shade.
Ctenophores are so fragile that little success in preservation has ever been attained. A 4 or 5% formalin solution sometimes works.
Flatworms are delicate and highly contractile. They are best preserved by placing them in a dish with just a little seawater and, when fully expanded, suddenly covering them with hot Bouin's solution. Final preservation is either in Bouin's or in 10% formalin. Bouin's solution gives off very disagreeable fumes. It may be obtained by consulting your druggist, a friendly chemist, or your nearest biological laboratory.
Annelids should be fixed in 10% formalin to harden the tissues and then transferred to 70% ethanol or stronger to prevent softening and disintegration.
Mollusks offer a variety of problems. Most soft-bodied opisthobranchs are best preserved by narcotizing with Epsom salts or magnesium chloride and then preserved in 70% ethanol. Octopus should be killed in freshwater, fixed with arms straight in 10% formalin for 48 hours or more, and then transferred to 70% ethanol. Squids should be placed directly in 10% formalin for 48 hours and then transferred to 70% ethanol.
Crustaceans may be preserved either wet or dry. If kept in preservative, they should be killed in freshwater to prevent their throwing off their legs and claws and then transferred to 70% ethanol. If they are to be dried, the same procedure should be followed, but after soaking in alcohol they can be laid out on absorbent paper, arranged in a lifelike manner, and thoroughly dried. When drying is complete, for best protection they should either be dipped or sprayed with plastic for permanence.
Starfish and brittle stars may be preserved dried. In order to dry them, starfish should first be soaked in 10% formalin for 24 hours and then dried in the shade. Brittle stars should be killed first by replacing seawater with a 3% solution of Epsom salts in freshwater. When dead, they should be transferred to 10% formalin for 24 hours and then dried in the shade. If either starfish or brittle stars are to be kept in liquid, they must be preserved in 70% ethanol. Formalin, even buffered with borax, will dissolve the calcareous plates and spines. Holothurians should be narcotized or put directly into 70% ethanol.
After the specimens have been preserved, they must be properly labeled. Although labels may have little or no value to some collectors who have several specimens only for their oddity, unlabeled or improperly labeled collections have no scientific value.
The label should be made of a heavy, 100% rag-content paper so that it will not disintegrate in the preservative. It should have written upon it, in either india ink or soft black lead pencil, at least the following information: scientific name of the species, the name of the describer, the locality where it was collected, the date collected, the name of the collector, and the name of the person who identified it.
I would be remiss if I did not here give a word of caution to the collector. Our shallow water marine life is faced with many difficulties: overcollecting; mindless killing; pollution; and the destruction of the habitats by dredging, filling, and bullcheading. It is incumbent upon us all to take no more specimens than are actually needed and to leave the collecting area in the same condition as we found it. This means filling in places we have dug out, turning back into their original positions large stones and logs overturned in our search, and leaving no litter of our own to mark our passing. Hopefully others may then find the same enjoyment when retracing our footsteps as we did when first we passed along the beach.
For information on collecting and preserving algae, see page 153.
Classification
The number of kinds of living animals far exceeds a million species. Very few of these have common names or are even known to anyone but a specialist in a particular group. For many years great confusion existed in attempts to bring order to the ever-increasing multitude of names, but in 1758 the Swedish naturalist Linnaeus proposed his famous binomial system of nomenclature. This system provided that each species be given two names—a generic name, always capitalized, and a specific name, which is never capitalized. The generic name shows affinity with other such species, the specific name the distinctness of each kind from all other kinds. The two names together comprise the name of the species, thus Callinectes sapidus, the blue crab. The names of genera and species are usually italicized.
In order to assist in research and bibliographic work, the name of the species is followed by the name of the person who first described it, thus Callinectes sapidus Rathbun. If the species is subsequently placed in a different genus from that in which it was originally assigned, the author's name is placed in parentheses. Thus the crab we know as Cronius ruber (Lamarck) was originally described as Portunus ruber by Lamarck.
Over the years a hierarchy of classification developed to put order in the animal and plant kingdoms and to show supposed relationships and evolutionary lineages. This hierarchy usually consists of the categories phylum, class, order, family, genus, and species. Only species names are lowercase. In some groups, such as the Crustacea, the relationships are so involved that a more complicated classification is required.
Phylum Arthropoda
Class Crustacea
Order Decapoda
Suborder Reptantia
Section Brachyura
Subsection Brachygnatha
Superfamily Brachyrhyncha
Family Portunidae
Subfamily Portuninae
Genus Callinectes
Species sapidus Rathbun
According to the International Rules of Zoological Nomenclature, the scientific names of animals are to be either Latin or, if in another language such as Greek, they are to be Latinized or treated as if they were in Latin. Most scientific names are descriptive, that is, they stress an important character, habits, geographical area where found, or bear an honorific name of a person, ship, or place. Thus an interpretation of the classification just given for the blue crab, Callinectes sapidus, is somewhat as follows.
Phylum—animals possessing jointed legs
Class—having a shell
Order—with ten legs
Suborder—crawlers
Section—short tail
Subsection—short jaws
Superfamily—short snout
Family—idae, the family ending on the name of Portunus, Roman god of the harbor
Subfamily—inae, the subfamily ending
Genus—beautiful swimmer
Species—savory, good eating.
A knowledge of Greek and Latin can often bring scientific names to life and can be informative as well as educational. Unfortunately few of us today have had a classical education. For those who wish to be able to translate the meanings of the names they encounter, the best book for the purpose is A Source-book of Biological Names and Terms by Edmund C. Jaeger, Charles C Thomas, Publisher, Springfield, Illinois.
This short discourse on names and classification will assist you in the use of this book and serve as an introduction to a fascinating field of study, a subject originated by Aristotle, brought into a semblance of order by Carolus Linnaeus, given a theoretical basis by Charles Darwin, and refined and multiplied by thousands of workers down to our day all striving to describe and name the living world around us.
Phylum Protozoa
The protozoans are mainly minute animals, each consisting of a single cell or of cells joined together to form colonies. They swarm in the seas, and microscopic examination of a drop of water or a scraping from a rock or piling will usually reveal an example. Most protozoans are free living, but some are attached or sessile, and some are protected by a skeleton of hard material such as silica or lime. Among the latter are the Foraminifera, which have a platelike shell of calcium carbonate with many small pores through which they extend their pseudopodia for feeding. Only a few species in our area are large enough to be seen easily by the naked eye.
CLASS SARCODINA
ORDER FORAMINIFERA
FAMILY SORITIDAE
Turtle grass foram
Archaias angulatus (Fichtel & Moll.)
The shell or test is about 1/4 in. (6 mm) in diameter, white, and coiled, the last chamber ending abruptly, forming an indentation in the side of the disk. This foram is very common on turtle grass blades where it is easily seen and collected.
Button foram
Archaias compressus (d'Orbigny)
The test is thin and flat, nearly circular in outline, formed of tightly coiled series of chambers. It is about 1/4 in. (6 mm) in diameter and is found, like the preceding species, attached to turtle grass blades in shallow water. These forams are very numerous.
FAMILY HOMOTREMATIDAE
Red foram
Homotrema rubrum (Lamarck)
The red forams form small splotches or spots of dark to bright red, calcareous growths on such hard objects as dead corals, mollusk shells, and rocks. The growth usually has one or more projections from the surface. This species is found growing in the reef tract from the sea surface to considerable depths.
Phylum Porifera
The Sponges
Sponges are sessile animals that grow attached to shells, stones, and other hard objects on the bottom. The living animal is formed of simply organized cells usually supported by a skeleton of fibers called spongin and calcareous or siliceous spicules, spicules alone, spongin alone, or it may have no skeletal structures. The outer skin is often very tough but is permeated by small pores through which water is pumped into the animal to filter out microscopic-sized food. The water is discharged through larger pores or holes called oscula. Reproduction is by fragmentation, budding, or the production of eggs and sperm.
The sponges found cast onto the beach are but the skeletons of former living animals and bear little resemblance to living sponges. Sponges are often amorphous with no distinct shape but some species grow in regular patterns. Thus identification usually requires microscopic examination of spicule preparations; only those species with characteristic growth patterns can be determined by eye alone.
Sponges grow in all types of habitats from intertidal rocks to the deep sea. Most are of no commercial value, but bath sponges are much sought after, being taken by hand with sponge hooks on long poles or by divers. Cleaned natural sponges still demand high prices in the markets; for many purposes they cannot be replaced by synthetics. Although there are several classes of sponges, only the class Demospongea is treated here.
CLASS DEMOSPONGEA
These sponges exhibit a great variety of shapes, sizes, and coloration. The skeleton may consist of spongin, siliceous spicules, both, or neither. There is a number of orders.
(Continues...)
Excerpted from Seashore Life of Florida and the Caribbean by Gilbert L. Voss. Copyright © 1980 Gilbert L. Voss. Excerpted by permission of Dover Publications, Inc..
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.
Table of Contents
Preface and about the new enlarged editionCollecting and Preservation
Classification
Phylum Protozoa: The Forams
Phylum Porifera: The Sponges
"Phylum Coelenterata: Jellyfishes, Hydroids, Corals, Sea Anemones, Sea Feathers, and Fans"
Phylum Ctenophora: The Comb Jellies
Phylum Platyhelminthes: The Flatworms
Phylum Nemertea: The Ribbon Worms
Phylum Annelida: The True Worms
Phylum Sipunculida: The Sipunculid Worms
Phylum Bryozoa: The Moss Animals
"Phylum Mollusca: Sea Slugs, Sea Hares, Nudibranchs, Octopus, and Squid"
Phylum Arthropoda: The Crustaceans
"Phylum Echinodermata: Sea Stars, Brittle Stars, Sea Urchins, and Sea Cucumbers"
Phylum Chordata: The Tunicates
Collecting and Preservation of Algae
The Plant Kingdom: The Algae
"Phylum Chlorophyta: The Green Algae, The Halimedas"
"Phylum Phaeophyta: The Brown Algae, Sargassum or Gulfweed"
Phylum Rhodophyta: The Red Algae
"Phylum Tracheophyta: Marine Phanerogams, Sea Grasses, Salt Strand Plants, The Mangroves"
Glossary
Selected References
Index