THE MUSEUM. 



69 



Fish." The Gonionemus vertens is a 

 most beautiful specimen of the small 

 Jelly fishes, about | of an inch in dia- 

 meter. It looks like a small umbrella, 

 with tiny streamers hanging from the 

 edge. Is perfectly transparent. These 

 little tree like forms puzzled naturalists 

 for many years until they were trans- 

 ferred to salt water acquaria and stud- 

 ied, when the above astonishing result 

 was discovered. It furnishes a very 

 good connecting link, as it were, be- 

 tween the animal and vegetable world. 

 Dactylometra quinquecirra is the more 

 common form of Jelly fish seen some- 

 times at twilight in immense numbers 

 floating over Long Island Sound and 

 adjacent waters. Owing to its large 

 size it is not sought after so much as 

 specimens, as it takes at least a quart 

 can to show off one nicely, and they 

 are frequently a foot in diameter. 

 Metridium marginatum is one of the 

 handsomest forms of the beautiful Sea 

 Anemones, the roses of the ocean. 

 These handsome little animals attach 

 themselves to the rocks, have a trunk 

 like a mushroom, and the top blos- 

 soms out like a rose. To preserve 

 them and still have the "top" blossom- 

 ed out is a delicate task, for the mom- 

 ent you touch one in the water it closes 

 up rapidly and nothing but a short 

 stump is left. They have to be col- 

 lected and placed in pails of sea water 

 when they very soon open nicely. 

 Then a small quantity of formolin is 

 added and after a day a little more 

 and in this way they are at the end of 

 four or five days thoroughly inoculated 

 with the formolin and die, fully expan- 

 ded It is a tedious job, but will re- 

 pay the collector. 



The EcJiinodermata include a wealth 

 of larger and varied forms. The As- 

 terias vulgaris, our most common star- 

 fish of the Atlantic coast makes a pret- 

 ty specimen when preserved in formo- 

 lin and fully expanded. Echinarach 

 nius parma, the Sand Dollar and Ar- 

 batia pnnctulata, the pretty little black 

 spiney Sea Urchin are most commonly 

 preserved dry. They make pretty 



specimens. Ophiura olivacea is fre- 

 quently called the Serpent Star and is 

 best preserved in formolin, owing to its 

 delicate form and fragility. Their tiny 

 arms quite resemble small snakes. 

 Thy one briar eus or Sea Cucumber is a 

 specimen not so commonly known. It 

 belongs to the curious order of Holo- 

 thurians, lives just below low tide and 

 found occasionally all along our Atlan- 

 tic coast. They run from 2 to 3 inches 

 long, but the alimentary canel is about 

 seven feet long, although the oval 

 stomach is less than one inch. They 

 are black, bushy, pear shaped, with 

 tentacles at the top, that can be quick- 

 ly and deeply retracted at any time. 



Deep Sea Mollusks and the Con- 

 ditions Under Which They 

 Exist. 



An address by Win. H. Dall before the Bio- 

 logical Society of New York. 



I propose to lay before you a state- 

 ment of the conditions which charac- 

 terize the life of Mollusks in the Deep 

 Sea, so far as they are known to us, 

 and to discuss briefly the effect of 

 these conditions upon the animals sub- 

 jected to them; the contrast which 

 their life presents to that of shallow- 

 water mollusks; the peculiarities ob- 

 served or the modifications induced by 

 the special environment; together with 

 some notes on interesting or remark- 

 able forms discovered in deep water. 



Once for all, it must be understood 

 that explanation of the deep sea fauna 

 has only begun; that the area swept 

 by the trawl and dredge compared 

 with that which remains unknown, is 

 almost infinitesimal; and, of the ma- 

 terial secured by dredging, a large 

 part is fragmentary and imperfect 

 In short what we know about the 

 deep-sea mollusks can only be regard- 

 ed as a foretaste of that knowledge 

 which future )ears may be expected 

 to supply. 



In all addresses of this sort biblio- 

 graphical references would be out of 

 place. I will only say that the liter- 



