1908.] 



CAPE VERDE ISLANDS SPOXGES. 



769' 



straight or slightly curved at their extremities; their average 

 length is 0-05 mm. and their width at base O'Oll mm. The 

 majority of the quadriradiates, like the triradiates, are sagittal. 



Text-fig. 161. 



Spicules ft'om Sycon caminatum. 



a = Tubar triradiates. h = Large oxeotes. c = Small oseotes. d = Gastral 

 quadriradiates. All X 120. 



The peristome consists of an irregular and complicated network 

 of spicules similar to those which occur in the other regions of the 

 sponge. There are large and small oxea like those crowning the 

 distal ends of the radial chambers, there are triradiates like those 

 of the tubar skeleton, and also tru'adiates and quadriradiates 

 resembling those of the gastral cortex. Some of the sagittal ti-i- 

 radiates in this region have the concave curve of the paired rays 

 towards the basal ray. The very minute hair-like oxea which 

 project from the ends of the chambers do not occur in the peri- 

 stomal region. 



This Sycon is most nearly allied to Si/candra {Sycon) helleri 

 Lendenfeld, a sponge found in the Adriatic Sea [17]. The species 

 differ, however, in a number of points, perhaps the most important 

 of which is the presence in m.j species of the remarkably well- 



49* 



