190 THE SPONGES OF THE WEST-CENTRAL PACIFIC 



this spination, it is rather close to the genus Oxeostilon in the family Hy- 

 meniacidonidae. It is further separated from Oxeostilon by the possession of 

 trichodragmas, which Oxeostilon lacks. 



Neoprosypa atina, new 



Text Figure No. 127 



This species is here represented by the following : 

 U.S.N. M. No. 22974, My No. M. 350, here designated as type and 

 U.S.N.M. No. 22975, My No. M. 351. Both of these were collected on July 



5, 1949, by diver, from the Pearl Pool near the western portion of the 



lagoon at Ebon Atoll. The depth was 1 to 3 meters, and the substrate 



was dead coral. 



This sponge is one of those which fill in the interstices of bushlike or 

 ramose dead coral. With some difficulty it was possible to excavate a frag- 

 ment of only sponge as much as 3 cm in diameter; larger specimens always 

 would contain considerable coral. 



The color in life was bright yellow, the interior being somewhat duller 

 than the exterior. The consistency was soft. 



The surface varies from smooth to smoothly undulating and is ostensibly 

 lipostomous, but it is possible to see where pores have been closed by mem- 

 branes pulled across them. These are about 80 /x in diameter. Oscules could 

 not be made out as distinct from inhalant openings. 



The ectosome is a fleshy dermis, but not easily detached because of the 

 rarity of subdermal cavities. Spicules project from it here and there, but not 

 close enough together so that the adjective hispid should be implied. The 

 endosome is rather crumb-of-bread, or micro-cavernous, in nature. 



The skeleton consists principally of megascleres in confusion. These are 

 styles, 6 tt by 300 //,, and oxeas, 7 ^ by 600 /a in dimensions. Each kind is 

 profusely covered with minute spines, or rugosities. Each spine is rather less 



Text Figure No. 127. Spicules of Neoprosypa atina. A: Oxea, X 182. B: Style, X 182. 



C: Head of style, X 781, showing the rugose surface. D: Pointed end of style, X 781. 



The raphides (from trichodragmas) are not shown. 



