32 PROCEEDll^GS OF THE GEOLOGICAL SOCIETY. [NoV. 20, 



suifaco of the ventral valve is entirely covered with minute, narrow, 

 elongated tubercles, from which rise numerous small tubular spines, 

 both the tubercles and spines becoming- smaller and shorter as they 

 approacli the margin. The dorsal valve is covered with small pits 

 and tubercles, from Avhich also rise slender spines, but apparently 

 less abundantly than on the ventral one. A large specimen measures 

 2 inches 5 lines in length, by 2 inches 2 lines in breadth and 1 

 inch in depth. 



Of this interesting species I liavc seen several specimens from 

 Chcderoo and Moosakhail. 



24. PiiODucTUs HuMBOLDTii, D'Orbiguy. PI. II. fig. C. 



Productus Humholdtii, D'Orb., Paleont. du Voyage dans I'Amerique 

 Meridionale, pi. 5. figs. 4, 7 ; 1842. 



Shell marginally transverse, rotundate, quadrate; ventral valve 

 moderately convex, with a wade shallow longitudinal sinus commen- 

 cing at a short distance from the extremity of the beak and extend- 

 ing to the front. Beak small and incurved ; hinge-line rather shorter 

 than the greatest width of the shell. Dorsal valve almost flat for 

 some distance, becoming slightly concave close to the margin, and 

 with a small mesial fold or elevation perceptible only close to the 

 front. The surface of the ventral valve is covered with numerous 

 small elongated tubercles arranged somewhat in quincunx, and from 

 wliich rise short tubular spines. 



The largest of Dr. Fleming's specimens measured 13J lines in 

 length by 16 in width and 6| in depth. Dr. Fleming found his 

 specimens at Kafir Kote on the west bank of the Indus. D'Or- 

 bigny's examples were obtained from Yarbichambi, on the Bolivian 

 table-land of the Andes. I must, however, observe that several of 

 the Indian examples bear so close a resemblance to some of our 

 British specimens of P. scahricidus, that they could be with difficulty 

 distinguished. 



25. StPwOPhalosia Moreisiana, King (?), var. PL II. fig. 8. 



Among the fossils stated to have been procured at Moosakhail, I 

 found two specimens of a shell which so closely resembled certain ex- 

 amples of the Permian Strophcdosia Morrisiana, that neither Messrs. 

 Kirkby, Howse, nor myself were able to distinguish it. In shape 

 it is nearly circular, with the same convexity of the ventral, and con- 

 cavity of the dorsal valve, the same relative proportions of the dorsal 

 and ventral areas, and, lastly, the presence of the same elongated 

 adpresscd spines which adorn the surface of the ventral valve in the 

 Permian specimens ; while the only difference consists in the appa- 

 rent absence of those minute radiating raised striae observable in the 

 perfect shell of King's species : but it must also be remembered that 

 this point of difference is only a negative one, and of slight value ; 

 for some specimens of the species from Tunstall Hill do not show 

 the character. The material at my command is not, however, suf- 

 ficient to enable mc to positively affirm the identity ; so that the 



