233 



deccanensis), &c., and in indurated clay with Gyrgonites, Paludhia;, 

 Physce, and Lymncei. 



Cypris cylindrica. Sow. (PI. LXIII. fig, 3.) 



The shell is of a green colour, somewhat mottled. It is cylindrical 

 in shape ;. the anterior margin rounded ; dorsal margin slightly con- 

 . vex tUl it approaches the posterior extremity, when it suddenly slopes 

 down, and is there bluntly pointed. The ventral margin is slightly 

 sinuated in the centre. The valves are somewhat gibbous on their 

 lateral portion. Internally, we see near the anterior margin a kind 

 of shelf, which extends across that portion of the shell, and is hol- 

 low underneath it — exactly resembling the shelf we see in the shells 

 of the genus Crepidnla. The surface of the carapace is very minutely 

 and slightly punctate. The edge of the ventral margin of the cara- 

 pace, both inside and outside, appears thickened, which thickening, 

 as seen on the inside of the shell, extends to the commencement of 

 the dorsal margin at either extremity, and there the shell both in- 

 ternally and externally is strongly and regularly ridged. 



Hab. Along with C. subglobosa in pools at Nagpur (JRev. S. 

 Hislop). 



Mus. Brit. 



This species appears to me to be identical with C. cylindrica, de- 

 scribed by Mr. Sowerby at the end of Mr. Malcolmson's paper on 

 the " Geology of the Sichel Hills," mentioned above. It was found 

 along with C. subglobosa in chert and indurated clay, along with 

 Unio deccanensis, Gyrgonites, Paludince, Physce, and Lymncei. The 

 chief difference consists in the recent shells being so slightly punc- 

 tured on the surface as to appear nearly quite smooth. Mr. Sowerby 

 thus describes it : — " Twice as wide as long, almost cylindrical ; 

 front very slightly concave ; the outer surface, which is very rarely 

 obtained, is punctured." 



Cypris cyhndrica. Sow., var. major, Baird. (PI, LXIII. 

 fig- 4.) 



The chief difference in this variety consists in its larger size, being 

 about double in all its dimensions. The typical or smaller variety 

 described above might at first sight appear to be merely the young ; 

 but an examination of a large series of that species shows them to 

 be completely adult shells. The internal shelf, the thickening of the 

 edges of the ventral margin, and the ridges on that margin, are all 

 indicative of a full-grown and adult shell. 



The colour of the shell of this variety is almost exactly the same 

 as the typical variety ; the form is the same, but the shelf is rather 

 larger, and there is some shght indication of a shelf at the posterior 

 extremity also, 



Hab. Along with the preceding (Rev. S. Hislop). 



Mus. Brit, 



Cypris dentato-marginata, Baird, (PI. LXIII, fig, ,5,) 

 Shell rounded- oval, swollen, smooth, of a light greenish colour 



