i62 Natural History Bulletin. 



without any perceptible leakage, and a long soaking in that 

 fluid is necessary before the Brachiopod will become tilled. 

 Another interesting fact is the extreme thinness of these shells 

 in comparison with those from shallow water. 



About twenty species of mollusks were found here. Prob- 

 ably the most striking fact concerning them is the great pre- 

 ponderance of the Gastropods over the Lamellibranchs, only 

 two species of the latter being found, and one of these 

 ( Chione ciugoida) was a dead shell taken from shallow water 

 near Key West. The only living species was a small Area, 

 from a depth of sixty fathoms, and hence not from the Pour- 

 tales Plateau proper. With the above exceptions, all the 

 specimens w^ere Gastropods. A species of Tcrcbra has a beau- 

 tifully sculptured shell in the form of a greatly elongated cone, 

 ornamented with revolving ridges with crescentic cross mark_ 

 ings between. Among the rarities may be mentioned two 

 specimens of ]^olit/a jiDiouia Chemn., which Tryon in his 

 •'Marine Mollusca of the United States." published in 1873^ 

 calls "the most rare and valuable American marine shell." 

 Neither specimen was living, however, but one contained a 

 hermit crab. A small and highh^ ornate Fiisits {F. eucosmius 

 Dall?), is characterized by tine revolving ridges and swollen 

 varices. While the colors of these deep-water mollusks are 

 seldom brilliant, the sculpturing and ornamenlation of form 

 renders them more beautiful, it seems to me, than their shal- 

 low-water representative?.. A small species of CoIuinbcUa. 

 for instance, looks as if covered with regularly disposed rows 

 of ]:)earl3' beads, while superficial ornamentation would seem 

 to reach the limit of extravagance in i\Iiircx cabritii Bernardi. 

 which is found in shallower water and has the added beauty 

 of a delicate pirik color. This elegant mollusk has the an- 

 terior portion greatly elongated into a slender, straight spine 

 beset with long, curved, horn-like processes which project at 

 right angles. Similar spines ornament the varices of the 

 shell. The species was found b\' the Blake as deep as one 

 hundred and sixty-four fathoms. Three other species of 

 Miircx were secured, all having conspicuous spines. They 



