370 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Holotype.—C&t. No. 21316, U.S.N.M. 



The considerable number of the specimens included in the collec- 

 tion makes it possible to eliminate from the species-idea minor fea- 

 tures due to accident or such as are strictly local. The characteristic 

 features are, then, the ectosomal crust of tangentially disposed oxeas, 

 the large promonaenes and somewhat smaller prodiaenes of the radial 

 bundles, the projecting protriaenes (including diaenes) with short, 

 strong clads, the difference in size and shape of the ectosomal and 

 choanosomal sigmas. Including the forms described below there is 

 very considerable diversity within the species not only in the matter 

 of shape, but as respects the hirsuteness of the surface and the termi- 

 nation of the efferent canals. But the skeletal peculiarities are es- 

 sentially the same throughout the series of specimens, and it seems 

 necessary to group all of the latter together as one species. 



The specimens from the different localities vary as to size of the 

 megascleres. For instance in the specimen from 5179 all of the 

 megascleres average a larger size than in those from 5152. 



The species is related to T. (Cinachyra) isis Lendenfeld (Lenden- 

 feld 1906, p. 143) from the northwest coast of Australia. It is also 

 certainly very close to T. (Chrotella) macellata (Sollas) from the 

 Philippines. No mention is made, however, in the case of the latter 

 species of the ectosomal crust of oxeas. The " cloacae " opening by 

 " oscula " in Sollas' species seem to correspond to the poriferous 

 pits of T. crustata. 



TETILLA (CINACHYRELLA) CRUSTATA forma HISPIDA, new form. 



At station D5442 was taken the largest of all the specimens of this 

 species. The sponge has a horizontal diameter of 115 mm. with a 

 vertical diameter of 75 mm., and is subspheroidal with a large flat- 

 tened base, approaching the hemispheroidal shape. 



Over the latero-superior surface are a few smooth areas, evidently 

 worn smooth, but the surface in general is covered with a continuous 

 fur of spicules projecting 2-3 mm., formed by protruding elements 

 of the radial bundles. This conspicuous fur makes the peculiarity 

 of the form,. It is useless to speculate as to its genetic value. Per- 

 haps any individual of the species growing up under similar condi- 

 tions would acquire it. 



The flattened basal surface, smooth in the center (worn perhaps), 

 is elsewhere thickly covered with spicules projecting outward and 

 downward 5-8 mm. 



The poriferous pits are numerous and of the usual type, some 20 

 mm. deep. Most are on the latero-superior surface, a few on extreme 

 upper surface. Many are closed, and in such cases the spicules 

 of the marginal fringe have come together, forming a papilla, 3-4 



