SEETULAEELLA CONICA. 21 



at nearly a right angle to the adnate part. Margin circular, even, frequently 

 surrounded by annular striae. 

 Gonosome not known. 



Dredged from a depth of 152 fathoms ofT the Florida Reef. 



This is a much smaller and more delicate form than any of the other 

 species of Cryptolaria in the collection, its hydrothecae having only about 

 half the diameter of those of C. ahies, the species which in this respect 

 approaches it most nearly. The fasciculation is not carried to the same 

 extent as in the other species, for it usually disappears from the pinnce at 

 a short distance from their origin, and those pinnae which are given off 

 near the summit of the stem are generally quite monosiphonic. 



In the monosiphonic portions the hydrothecaj are seen to arise from the 

 sides of a common tube to which they are generally adnate for more than 

 half their height; they are here provided with a distinct floor, and are 

 entirely differentiated from the supporting tube. In the fascicled portion 

 they are, as in all the other species, deeply immersed and in great part 

 concealed. 



The pinnse are so disposed that those of one side do not arise from the 

 middle point of the space opposite to the interval between two pinnse of 

 the opposite side, but from a point quite near to one end of this space. 



Family SERTULARIDiE. 

 Genus SERTULARELLA Gray. 



Sertularella conica. 



PL XV. Figs. 6, 7. 



Trophosomc. — Hydrocaulus attaining a height of about an inch and a 

 half, simple or with an occasional short branch, not fascicled. Hydrothecae 

 distant, each springing from a point close to the distal end of an internode, 

 tumid towards the base, much narrowed towards the orifice, slightly marked 

 with transverse corrugations on its upper side. 



Gonosome not known. 



Dredged southwest of Tortugas from a depth of CO fathoms. 



Sertularella conica is a rather rigid species. It is distinguished from S. 

 poli/zonias by its nearly simple habit, by the greater distance of the hydro- 

 thec« from* one another, and by their more conical form, resulting from 

 their rapid narrowing towaids the orifice. 



