Sollas — On the Geocline Genera, Synops, and Sidonops. 277 



of hops and Synops are found together in the same area, but those 

 of Isops are always smaller than those of Synops, which are evidently 

 more fully grown. 



Whatever may be the fate of Vosmaer's Synops, it is quite clear 

 that my Synops is a misnomer, and must be replaced. I propose 

 to substitute for it Sidonops. When making my preliminary ex- 

 amination of the Challenger material, I had assigned in MS. to the 

 sponges wrongly called Synops the name Kalops : my subsequent 

 error is all the more unintelligible. Kalops, however, is pre- 

 occupied. 



This renders necessary the following corrections : — 



On page cxlix. of the Challenger Report (vol. xxv.), for Synops 

 read Sidonops, and for the type species substitute Sidonops neptuni, 

 SolL, for Synops pyriformis, Vosm. 



For Synops read Sidonops in each of the following cases : — 



Synops neptuni, p. 227 ; Synops nitida, p. 231 ; Synops vosmaeri, 

 p. 234 ; Synops macandreivii, p. 265 ; and for Synops pyriformis, 

 Vosm., p. 266, read Isops pyriformis, 



In conclusion, I have to express my best acknowledgments to 

 Dr. Yosmaer for affording me the opportunity of making this 

 •correction. 



