1920.] Further Notes on the Genus Camptoceras. 3l 
being congeneric with C. wei — se seo a Here again, 
however, C. subspinosum ann t form, the more 
elongate shape of its shell sah jin dentiguie whorls bringing 
it distinctly nearer to the extreme species of the genus than is 
C. lineatum. 
Considering the four species of Camptoceras now known 
together, the propriety of separating them from the genus 
Bullinus may possibly be doubted. The shells of such species 
as B. aliciae (Sowerby) and B. acutispira (Tryon) are not very 
different from those of C. subspinoswm in general structure and 
the radulae of the two genera have a somewhat similar facies. 
In no species of Bullinus, however, are the whorls so oblique 
or so angulate, or the suture so broad and canal-like as in 
Camptoceras. The radular teeth,! moreover, are much fewer 
in each transverse row in Camptoceras and have the sharp 
point of the cusps much less well developed and the gill is not 
lobose. We are of the opinion, therefore, that Camptoceras 
should be placed a asnca sd in the subfamily Bullininae but 
not in the genus Bullin 
ive here, to facilitate ee ange of the subfamily, 
genera and species, a brief synopsi 
Subfamily BULLININAE. 
Planorbidae in which the shells are ovoid or elongate and 
acuminate, never disc-shaped 
Key to the genera of Bullininae. 
1. Shell es the whorls more - less swollen, 
the suture linear or almost so .. . Bullinus. 
2. Shell ith the whorls angular or subangu ular. 
and extremely oblique, the suture ue 
broad and deep .. . Camptoceras. 
Genus Camptoceras, Benson. 
1843. Benson, Calcutta Journ. Nat. Hist. nt P. 465. 
1855. id., Ann. Mag. Nat. Hist. ®) XV, 
As. 
1914. Gude, Faun. Brit. Ind. oll II, p. 4 
1919. a yes at Papers Mus. Zool. Univ. Michigan, 
” 0 
No. 
1919. Mieloaia ia ‘and Prashad, Journ. As. Soc. Bengal 
(n.s.) XIV, p. 458. 
Key to the species of Camptoceras. 
1. Shell extremely elongate, at least 3 times as high as 
road, without strong spiral sculpture. 
t See Cook, Proc. Zool. Soc. London 1899, pp. 136-143. 
