Gemis Cyp7'CEa. 207 



white, on columella red, but not extending far over the 

 base. Eastern Seas. Length i^^ inch. 



G. moneta (L.). 



C Annulus (L.). 



0. obvallata (Lamk.). 



Although kept distinct here for the sake of convenience, 

 I think these three are really forms of one species. Typi- 

 cally they are all distinct, and easily discernible, but the 

 varieties are many, especially of moneta, of which the best 

 known is icterina (Lamk.) a smooth variety. Barthelemeyi 

 (Born) is a distorted produced variety from New Caledonia. 

 M. A. T. Rochebrune has added ten so-called species to 

 this section from moneta and annulus. He gives the 

 distribution as extending from Japan to Corsica {G. Merca- 

 tonun {Rochbr.), and from the Sandwich Isles to Zanzibar. It 

 may probably have been accidentally introduced in the 

 Mediterranean Sea. Most of these new forms are figured 

 in Tryon. Man. of Conch., Cyp., pi. x., xi., and xxiii. 



C. No2L7nee7isis (Marie) is a curious form of anmihis with 

 double orange lines on the back of the shell. 



C. obvallata (Lamk.). 



{a) calcarata (var. nov.). 



Shell dull, chalky white, uncoloured, otherwise as in the 

 type. Two live shells in good state of preservation exactly 

 similar in Mr. Williams' collection. The geographical distri- 

 bution of this is not so extended as are the former and better 

 known species. It is recorded, however, from Cook, Society, 

 and Paumotus Isles (A. Garrett), Australia, and New 

 Caledonia. The depressed centre of the dorsal surface is 

 very characteristic. 



(XII.) Upon Variation. — Far be it from me toaugment the 

 mass of literature that of recent years has flooded the world 

 on the most important and, as yet, only partially solved 

 question of variation and limitation of species. The doctrine 



