A MARIJVU BIOLOGICAL LABORATORY 



455 



tliiis 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 thick- 

 ly strewn over the bottoms of the ponds. Of starfish we collected 

 three forms {Echinaster, Asteropectin, and Astorina). For holo- 

 thurians 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. 



Fig. 3. The Marine Laboratory. 



try any experiment we might, they would always end with nega- 

 tive results. About the time we considered them fully narcotized 

 they began contracting the muscles of the body walls, then sud- 

 denly eviscerated themselves. One very interesting form (Synapta 

 vivipara) was found in great numbers growing among the fila- 

 ments 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 impor- 

 tant part of our expeditions. For this purpose we used water 

 buckets and open jars. The various specimens were distrib- 

 uted in different vessels, so as not to be crowded ; these were 

 allowed as much fresh sea water as possible, which was changed 

 repeatedly. 



