264 KEY. 0. p. CAMBRIDaE ON NEW SriDEKS. 



such as were presented in the specimens of S. Edwardsii ; my 

 doubts were thus dissipated. Nevertheless a decisive circumstance 

 shortly after occurred, which proved that my first opinion was the 

 better founded. I received a specimen of the sea-bottom from the 

 Bay of Colon, Aspinwall, and amongst a great number of shells I 

 discovered some specimens of a variety of O. Uratocinctum. Some 

 of these were young, others adolescent or adult ; but amongst them 

 I found a beautiful specimen presenting the three stages of 

 growth united in the same shell, and exhibiting the same deviation 

 as that observed in S. Edwardsii, a deviation equally marked in 

 some specimens in which the primary and second stages only were' 

 united. The establishment of such a fact evidently shows that 

 the species referred to Strelloceras or PMeloceras merely re- 

 present fortuitous instances of the persistence of the shell of the 

 primary stage upon that of the second, and sometimes even upon 

 that of the third, the first and second remaining united to one 

 ;another as well as to the third. 



Descriptions of a New Genus and Six New Species of Spiders. 

 By the Eev. O. P. Cambeidoe. Communicated by Jambs 

 Salteb, Esq., r.KS., r.L.s. 



(Plate IX.) 

 [Eead June 18, 1868.] 



Introduction. — It will be long, probably, before the study of Arach- 

 nology becomes as popular as that of some other classes of the 

 " Articulata." 



Spiders and their allies have neither the intrinsic beauty of the 

 " Coleoptera " to attract the collector, nor the varied habits and 

 transformations of the " Lepidoptera " to commend them to the 

 incipient student of Entomology ; hence, perhaps, in great mea- 

 sure, it is that the systematic students of Arachnology in Europe 

 a.t the present time may be more than numbered on one's fingers' 

 €nds, while Coleopterists and Lepidopterists are "legion." 



There are difficulties also in studying the habits of Spiders, 

 which do not exist in respect to the Lepidoptera generally. The 

 habits of these latter are commonly to be observed by day, 

 whereas the majority of the Arachnida are nocturnal ; and then, 

 again, I think it is true that the habits of the rapacious classes of 



