76 ■ THE SPONGES OF THE WEST-CENTRAL PACIFIC 



GENUS NARA, new 



The genus is erected to be, at least temporarily, within the family Hal- 

 iclonidae. Its skeleton is absolutely typical of the family, but the proto- 

 plasmic portions are so very different that some other family location may 

 ultimately be necessary. This is a genus of dense, soft, jelly-like or colloidal 

 protoplasm, permeated by a very diffuse, typical isodictyal reticulation of 

 thin fibers. The spongin occurs chiefly at the nodes. The spicules are thin 

 oxeas only. The genotype is the following species Nara nematifera. The 

 generic name is derived from the Greek for "flowing," because of the soft 

 consistency of this sort of sponge. 



Nara nematifera, new 



Text Figure No. 46 



This species is here represented by the following : 

 U.S.N.M. No. 22980, My No. M. 357, here designated as type, collected 

 July 5, 1949, by diver in the Pearl Pool in the western portion of the 

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

 dead coral. 



This species is abundant throughout the whole atolls of Ebon and Ailing- 

 lap-lap. 



Text Figure No. 46. Two 

 of the spicules (oxea) of 

 Nara nematifera, X 781. 



The shape is incrusting, about 1 mm thick, spreading laterally indefi- 

 nitely, often covering ramose coral almost completely. 



The exterior and interior color in life was a bright purple of a peculiar 

 transparent or translucent nature. The specimens became green in alcohol. 

 One of the most conspicuous field characteristics was the invariable presence 

 of conspicuous pale parallel threads about 2 mm apart and indefinitely long, 

 at least many cm in length, and about 50 jx to 150 /a in diameter. The con- 

 sistency, as noted above, was softly colloidal. 



The surface is shiny smooth, and no pores nor oscules can be made out. 



There is no separate dermis or other ectosomal specialization. The 

 endosome is a dense jelly, permeated by the above-mentioned strands, and 

 contains definite flagellate chambers, 30 ;x in diameter and spherical in shape. 

 It is also permeated by an isodictyal reticulation. 



The skeleton consists of very thin oxeas, 1 it by 90 /x to 2 fi by 95 /a in 

 dimensions. These are united at the ends in the above-mentioned reticulation 



