OHITOK i: LDflJ \. 



This section or sabgeniu represents a further development of the 



AcMiithoplcuroid characters which sonic A uM ralasian ,-peries of the 

 restricted p-nus ChUmi a-.-ume. In ("//. / ///./ ,-/ ////'-, lor example, 

 the 'micro is median, the posterior teeth tend forward .-om-wh;i- 

 sinu- i- smooth or only very ohsoletcly denticulate, and the girdle- 

 scales are striated and rather separated. I" &-i,-,'n<-hiin,i the mucro 

 is -lightly more posterior, the teeth slightly more tilted forward ; 

 the sinus is smooth, and the girdle scales still more separated. ('I. 

 il* could be placed almost as well in Schrncliitnn as in 

 8. *. ; the necessity of reducing Sclerochiton to the rank of a 

 section under ( 1 liifnn will therefore be apparent. The girdle-scales 

 hear a certain resemblance to those of En<>i>I<x-liit<>n, but this is a 

 purely accidental similarity, dependent upon their separation on the 

 surface of the girdle. 



C. MILES Carpenter, n. sp. PL 46, figs. 1, 2, 3, 4, 5' 



Shell solid, rugose, oval, depressed, generally eroded ; dorsal 

 ridge rounded, hardly defined ; mucro behind the middle, nearly 

 flat; apices of the valves prominent, obtuse. Ashen, spotted with 

 black-brown. Central areas transversely pretty regularly riigulose, 

 the wrinkles appressed ; lateral areas hardly elevated, moderately 

 well denned, conspicuously rugose, rugae subradiating, granose ; the 

 end valves similarly sculptured. 



Interior having the anterior valve with about 11, central 1, pos- 

 terior valve obscurely 9-11, slits. Teeth of posterior valves directed 

 forward, strongly callosed inside above the slits, sulcate outside ; 

 the rest of the valves having the teeth sulcate outside and pect- 

 inated at the margins. Eaves moderate, solid, deeply grooved. 

 Sinus deep, wide, wavy, smooth ; sutural laminae united. 



Girdle (pi. 46, fig. 1.) maculated, ornamented with large, solid, 

 more or less separated scales which are striated outside ; no hairs. 

 (Cpr.}. Length 30, breadth 17* mill. ; divergence 130. 



Tnrrr* Sf I'll iff (Mus. Cuniing, no. 42.) 



A variety is described as being a little narrower, and blackish, 

 hardly maculated. 



Section KADSIA Gray. 



i;,i,l*i>i ( JIIAY, P. /. S. 1847, p. 126. Type Ch. /*/,//- 

 Girdle and shell like C/iiti>//, except that the insertion-plates of 

 the intermediate valves have two or several slits. 



