THE SPONGES OF THE WEST-CENTRAL PACIFIC 101 



clictyal reticulation. The endosome also is isodictyal and contains very- 

 numerous round flagellate chambers 40 /x in diameter. 



The skeleton consists of oxeas, 1.5 ^ by 93 ja to 2.5 ti by 112 /a. It might 

 be said that in general they were about 2 /a by 100 /a. 



This, like the preceding species, is sharply set off from others in the 

 genus Pellina by the very small size of its spicules. Since the preceding 

 species came from the same part of the world, it might be expected that they 

 would be closely related to each other ; but, far from this being the case, it is 

 suggested here that they may even deserve separate genera. The two preced- 

 ing species, eusiphonia and pinella, belong in a group of the genus Pellina 

 which is well characterized by that species first described as Eumastia sitiens 

 by Schmidt, 1870, page 42. Sponges in this group are little more than tubu- 

 lar processes with scarcely any basal mass at all. They are usually pale in 

 color and very fragile. The species carbonilla belongs instead in a subdi- 

 vision of the genus Pellina which is well characterized by the sponge first 

 described as Spongia carbonaria by Lamarck, 1814, page 375. Sponges in 

 this group have a very considerable basal mass ; the walls of the ascending 

 processes are relatively thick; and the color is regularly dark and commonly 

 black. The type of the genus is in the first of these two subdivisions. There- 

 fore, if a new genus were to be established, it should be one receiving Pellina 

 carbonaria as type. 



The specific name represents a diminutive of carbonaria, because the 

 sponge is like the following species, but with minute spicules. 



Pellina carbonaria (Lamarck) de Laubenfels 



Text Figure No. 63 



This species is here represented by the following : 

 U.S.N.M. No. 23113, My No. M. 495, collected September 1, 1949, by 

 divers in Iwayama Bay, Koror, in the Palau Islands. The depth was 2 

 meters, and the substrate was dead coral. 



The shape is sprawling, with chimneys rising up to 4 cm high. These 

 tubular processes are about 8 mm in diameter and have walls less than 1 mm 

 thick. 



The exterior and interior color in life was black, and the consistency 



fragile. 



Text Figure No. 63. Two of the spicules (oxea) of Pellina carbonaria, X 781. 



