154 



THE SPONGES. 



Iophon indentatus also resembles in surface appearance Alebion proximum 

 Eidley (Ridley, 1881, p. 114), another of the species combined by Ridley 

 and Dendy. But the styli here are 158 /x x 9 /x, and thus much smaller than 

 in my sponge. Moreover, the skeletal reticulum is described as composed 

 of primary fibres, five to six spicules thick, running from the base to the 

 surface and crossed by secondary bars approximately at right angles, — an 



arrangement not found in 7". indentatus. 



V J 



The "Challenger" specimens of Iophon pattersoni R. and D., which I 

 have examined, differ markedly in surface appearance from my form. 

 They are, as Ridley and Dendy describe them, massive and amorphous. 

 I may add that they are honeycombed with comparatively large canals, 

 which open over the whole surface. The spines and tylotes (R. and D., 1887) 

 are considerably slenderer than in I indentatus. On the other hand, I find 

 the bipocilli are of about the same size as in my form, and have a similar 

 shape, the smaller end being denticulate. But this point of resemblance 

 probably means little, since minute bipocilli with denticulate small end also 

 occur in Iophon radiatus Topsent (Topsent, 1901 a, p. 22, Plate III. Fig. 13) 



and in Iophon lamella indivisus. 



Topsent (1892 under Dcndoryx (Iophon) nigricans Bwk.) criticises Iophon 

 pattersoni sensu Ridley and Dendy, and is disposed to regard it as a hetero- 

 geneous group, on the score that some of the forms which Ridley and 

 Dendy combine, and which have been taken several times, are readily dis- 

 tinguishable. I must say that I find the published data for the union of 

 these several forms inadequate. I therefore designate my sponge as a new 

 species, although Iophon pattersoni as conceived by Ridley and Dendy is 

 probably comprehensive enough to include it. 



