THE SPONGES OF THE WEST-CENTRAL PACIFIC 251 







Text Figure No. 174. Spicules (spherasters) 

 of Chondrilla nucula, X 782. 



U.S.N.M. No. 22858, My No. M. 152, collected July 7, 1949, from the open 

 ocean west of Ebon Atoll near Rube Point. The depth was 3 meters, and 

 the substrate was dead coral. 



This species is semi-incrusting, up to 1 cm thick and as much as 7 cm in 

 diameter. 



The color in life varied from slaty, almost black, to quite black, but the 

 interior was only grayish drab. The consistency varied from cartilaginous to 

 jelly-like. 



The skeleton comprises only the mesogloea and microscleres. The latter 

 are exclusively spherasters 20 /x to 32 /x in diameter. 



This species was first described by Schmidt, 1862, page 39, from the 

 Mediterranean. It is also very common throughout the West Indian region. 

 There is one record from the Australian region by Burton, 1924, page 206. 



Chondrilla acanthastra, new 



Text Figure No. 175 



This species is here represented by the following : 

 U.S.N.M. No. 22916, My No. M. 221, here designated as type, collected 

 September 1, 1949, by divers in Iwayama Bay near Koror in the Palaus. 

 The depth was 2 meters, and the substrate was dead coral. 



This species is incrusting, about 1 mm thick and upwards of 15 cm in 

 lateral dimensions. 



The ectosome and endosome color in life was grayish drab, and the con- 

 sistency was between that of jelly and cartilage. 



The surface was shiny smooth and lipostomous. 



The ectosome consists of an exceedingly thin fleshy dermis, and the 

 endosome is also very jelly-like or fleshy. 



The only skeleton, other than the ubiquitous mesogloea, consists of very 

 distinctive microscleres. These are euasters but not oxyasters ; instead, they 

 are chiasters with blunt terminations. Furthermore, the rays are conspicuously 

 and entirely spiny. The diameter varies from 17 /x to 22 fi. 



Text Figure No. 175. Spicules (microspined euasters) of 

 Chondrilla acanthastra, X 782. 



