THE SPONGES OF THE WEST-CENTRAL PACIFIC 



185 



The color in life was orange; and the consistency, other than that of the 

 obvious spicules, was a softly colloidal sol. 



The surface is lumpy and hispid with optically evident spicules protrud- 

 ing at least 3 mm beyond the surface. These are not close together as in 

 plush or velvet but are separated from one another by about 200 /a. No pores 

 nor oscules could be made out. 



There is little or no ectosomal specialization, and the endosome is chiefly 

 protoplasmic, other than the spicules which may be described under the 

 heading of skeleton. 



The skeleton consists primarily of enormously long megascleres, con- 

 sistently about 15 fi in diameter. These stand perpendicular to the substratum, 

 run through the entire thickness of the sponge, and protrude about 3 mm 

 beyond its surface, so that the total length is about 5, 6 or even 7 mm. Most 

 of these spicules were broken in the process of making mounts for micro- 

 scopical study. A very few which were not broken proved to be strongyles, 

 but inasmuch as numerous of the fragments showed pointed ends, it must be 

 that some of the spicules are styles or even oxeas. In any case, these are all 

 of the same category. A second type of spicule is a somewhat bent, smooth, 

 sharply pointed oxea, about 7 ti by 255 /i. Spicules of this type are strewn 

 in confusion inside and throughout the flesh of the sponge. The microscleres 

 are trichodragmas, individual raphides of which are about 0.3 /x by 60 ll in 

 dimensions. 



This species hispida constitutes a fifth for the genus and is sharply set 

 off by the enormous length of the larger category of spicules. In the other 

 species these do not exceed 1 mm at the most. Rhaphisia ambrosia de Lauben- 

 fels, 1936, page 135, from the West Indies, lacks the trichodragmas. 

 Rhaphisia laxa Topsent, 1892, page xvii, from the Mediterranean, the type 

 of the genus, lacks the longer category of spicules. Rhaphisia ramosa White- 

 legge, 1906, page 463, from Australia, is unique in the genus for having 

 ramose or clathrous form ; all its spicules are quite small as compared to the 

 others in the genus. A fourth species was first described at Thrinocophora 

 spissa by Topsent, 1892, page 124, and was referred to Rhaphisia by the 



Text Figure No. 123. Spicules of Rhaphisia hispida, X 182. A: Oxea; the entire spicule 

 shows, but in two parts. B: Head region only, of strongyle or style. C: Raphide, from 



the trichodragmas. 



