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Page:Popular Science Monthly Volume 44.djvu/469

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A MARINE BIOLOGICAL LABORATORY.

thus forming a number of quiet ponds and canals. We found life very abundant here. Upon the mangrove roots great clusters of Clavelina, simple ascidians, and colonies of hydroids hung near the surface of the water. Battery actinians and Botryllus grew in the warm waters, attached to blades of eel grass. Echinoderms were very abundant. Sea urchins (Strongylocentrotus) were thickly strewn over the bottoms of the ponds. Of starfish we collected three forms (Echinaster, Asteropectin, and Astorina). For holothurians no other place along the coast was better. They were profusely scattered about over the muddy bottoms of the ponds. Some were dark brown, others large and spotted, growing to a length of eight and ten inches. Our experience in collecting and preserving these large holothurians was always exasperating, for,

PSM V44 D469 The marine laboratory.jpg
Fig. 3.—The Marine Laboratory.

try any experiment we might, they would always end with negative results. About the time we considered them fully narcotized they began contracting the muscles of the body walls, then suddenly eviscerated themselves. One very interesting form (Synapta vivipara) was found in great numbers growing among the filaments of a certain alga in the ponds. Sponges, gasteropods, and annelids were also numerous about the mangroves.

Taking the animals alive to the laboratory was an important part of our expeditions. For this purpose we used water buckets and open jars. The various specimens were distributed in different vessels, so as not to be crowded; these were allowed as much fresh sea water as possible, which was changed repeatedly.