Simpson — A Revision of the Gorgoncllidae. 86 1 



layer of longer densely tuberculate spindles, having a bare median space 

 more or less clearly indicated." 



Wright and Studer, with these facts as a basis, give the following 

 diagnosis : — 



" The colony is upright, branched, with a thin coenenchyma and 

 protruding verrucae, which arise perpendicularly, and appear to be 

 terminally truncated. The polyps arise from either side of the' stem and 

 branches, leaving a middle space free. The spicules form a cortical layer of 

 small double-clubs and an internal layer of long densely warted spindles." 



The following species have been from time to time referred to this 

 genus : — 



N. diclwtoma (Gray). 



N. mauritiana (Gray). 



N. laxa Whitelegge. 



N. flahellata (Whitelegge). 



N. reticulata Thomson and Simpson. 



N. imstidosa Thomson and Simpson. 



An examination of the type-specimen of Scirpcardla moniliforme Wright 

 and Studer, in the Collection of the British Museum, has revealed the fact 

 that this species should Idc included in the genus Nicella. Thomson and 

 Henderson also referred VcrruceUa flahdlata Whitelegge to this genus, so 

 that the generic diagnosis has been emended to include these forms. 



Thomson and Simpson (xli., p. 267) referred a specimen in the Littoral 

 Collection of the Indian Museum to this genus under the name Nicella 

 fxCstvlosa, with the following reservation : — 



" It is with some hesitation that we refer this type to the genus Nicella. 

 It is a matter of no small difficulty to distinguish between Nicella, Gorgonella, 

 and Verrucella. . . . 



" Our specimens approach Nicella in several respects, though agreeing 

 with none of the deseiiljed species ; and as the positive characters of the other 

 genera are absent, we feel justified in making a new species to include these 

 forms." 



The present study of this genus has, however, convinced me that the 

 presence of the abnormally large spindles is a character which cannot be 

 overlooked; so that, while still acknowledging the specific rank of the 

 specimens under consideration, I would suggest their withdrawal from the 

 genus Nicella, but until a revision of the species of Verrucella and Gorgonella 

 has been made I would not hazard an opinion on their generic position. With 



[dB-2] 



