104 



THE SPONGES OF THE WEST-CENTRAL PACIFIC 



Text Figure No. 65. Adocia viola. A: Portion of a dermal pore, showing the sieve or 



network which it contains, X 182. B: Spicule with modified ends, X 781. C: Very thin 



spicula, perhaps juvenile, X 781. D: Oxea of more commonplace shape, X 781. This 



latter was from specimen number M. 526. 



The surface is punctiform. Often the partitions between pores are as 

 narrow as only 50 p. The gross pores are about 250 p in diameter ; and the 

 actual pores, which perforate the skin across the skeletal pores, are from 20 p 

 to 60 p in diameter in the type specimen but 30 p to 70 p in some of those 

 from Ponape. The oscules vary in size up to about 5 mm in diameter — 

 rather larger in specimens from Guam than in those from Ponape. The dis- 

 tance apart is 1 to 3 cm. 



The ectosome is not typical of Adocia but must be so classified, because 

 it definitely does show a tangental isodictyal reticulation (although this is 

 missing in places and often rather confused). The endosome also falls short 

 of typical Adocia architecture. Much of it shows the isodictyal reticulation 

 which would be expected ; but there are also portions in confusion, and there 

 are vague ascending tracts. 



The skeleton consists of spicules very loosely attached to one another by 

 dubious spongin and usually attached only at their ends. These are oxeas 

 3 /x by 120 [x to 4 fx by 116 p. Specimen No. M. 421 had many spicules with 

 a very peculiar modification. Each end was sharply truncated, as though the 

 points had been cut off. In other cases, still more numerous, it was as 

 though the end had been cut off and a series of successively smaller ends then 

 superimposed, so that the termination comes down rapidly by a series of 

 steps. It is rather clear that such a spicule was originally (in this case) an 



