92 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 81 



The oxyhexasters are common, but not abundant, in the choano- 

 some, as well as in the subdermal and in the subgastral spaces. They 

 are characterized by rather longer terminals, as compared with the 

 principals, and are slender, quite smooth on the surface, and, though 

 bent at the base, are nearly straight for the rest of their length, and 

 so diverge from one another as to give a spherical shape to the entire 

 spicule. This measures 110/,t to 120/a in diameter. Principals bearing 

 less than two terminals probably never occur; there are two or 

 three in most cases. 



The only kind of discohexaster present is comparable to the micro- 

 discohexaster of certain other rossellids. It measures only 3.04 mm 

 in diameter. The convex disk at the outer end of each fairly strong- 

 principal bears a bunch of numerous and exceedingly fine divergent 

 terminals, each of which ends in a minute terminal knob. The shape 

 of the entire rosette is spherical. In some parts the discohexasters 

 in question were found only occasionally ; in other parts of the same 

 specimen they were quite common, occurring near the subdermal or 

 subgastral regions, where they seem to be present in nearly equal 

 numbers to, or are somewhat more numerous than, the oxyhexasters. 



The described spiculation seems to come nearest to, and indeed 

 closely resembles, that of Vitrollula fertUis. But, as the parenchy- 

 mal hexactins are lacking, I should prefer not to make a definite 

 specific determination. 



An interesting fact regarding the specimen is the presence of cer- 

 tain peculiar small bodies lodged in large numbers among the tis- 

 sues of the choanosome. Ijima has already noted these in Stauro- 

 calyptus glaber. To the naked eye they appear as whitish spots of 

 various sizes of about or less than 0.5 mm diameter. Under the mi- 

 croscope the body is found to be a reticular mass of no definite shape,^ 

 consisting of an irregular rigid framework of microtuberculate 

 beams. The mass is always completely transversed by a few par- 

 enchymal diactins of the sponge. These reticular bodies treated of 

 are also like those described by F. E. Schulze from the buds borne 

 on the prostal lateralia of Rhdbdocalyptus mirahilis. 



BATHYDORUS, jQ species 



Several poorly preserved fragments were obtained from two sta- 

 tions: No. 4769 (Bowers Bank, Bering Sea, depth 244 fathoms), 

 and No. 4770 (Bowers Bank, Bering Sea, depth 247 fathoms). 

 As the specimens are macerated and broken into several fragments, 

 it is impossible definitely to determine whether they are identical. 



The principal parenchymalia are the rather numerous and elon- 

 gated bowlike diactins, 160jli to 200iu long, the middles of which are 

 not always externally marked by a swelling. They are practically 

 smooth on the surface, gradually tapering toward both ends. 



