1859.] nisior — fossil shells of nagpur. 175 



crassis, obscure radiatis ; margine ventrali intufl crenato ; natibus promiindis, 

 ad apices ornatissime radiato-rugosis. Diam. 1 ; long. 1'5; lat. 24 una 



Karuni, common. Dedicated to the llcv. P. Hunter. This shell 

 very much resembles the last. The valves of both have an inward 

 radiated structure, Avhich becomes quite apparent on their surface 

 being weathered. But besides a difference in size between them, 

 the anterior margin of U. Deccanensis, which is the larger species, is 

 remarkable for its shortness, seeming as if it were entirely rounded 

 off, whilo in U. Hunter I it is produced to an average length. 



TJnio mamillatus, sp. nov. PI. YII. fig. 26. 



27. testa subcuneiformi, inaeqmlaterali ; postice producta, angulata, compressa ; 

 valvulis crassis et una matnillarum serie instructis ; natibus elevatis, ad apices 

 decore radiatis. Diam. 10; long. 2 - 3; lat. 39 unc. 



Karuni, frequent. There is no species of Unto in India at present 

 to be compared with that now under consideration. The young of 

 Unio jparma from Tcnasserim, I observe, is furnished with tubercles, 

 but in a double row ; and the shell is moreover much more orbicular. 

 The well-known U. sjrinosus is the species which seems to come 

 nearest ours, especially in the position of its single row of appendages. 



Unio imbricates, sp. nov. PI. YII. figs. 27 a, 27 b, 27 c. 

 U. testa suborbicidari, subffiquilaterali, intcrdum postice valde angulata ; valvulis 

 squamarum, seu magis iiubricum, serie una instructis; margine ventrali intus 

 crenato ; natibus elevatis. Long. 2'2 ; lat. 2*3 uuc. 



Frequent at Mekalgandi Ghat along with U. Malcohnsoni. This 

 shell is formed on the same model as the preceding in regard to the 

 situation of the row of ornamentation, which is about the centre of 

 the valve, and anterior to the umbonal ridge; but the shape of the 

 valves and of the ornamentation in the two cases is very dissimilar. 



Unio Carteri, sp. nov. PI. YII. fig. 28. 

 U. testa l«vi, transversa, subelliptica, compressa, imcquilaterali, ad basin 



emarginata; vavulis crassiusculis ; natibus prominulis, ad apices elcganti.ssiuio 



radiatis. Long. l - 7; lat. 3 - 5 una 



Karuni, rather rare. This handsome shell, which, except in its 

 being longer, exhibits a close affinity to C. Jamesianus of Lea, I 

 propose naming after my friend S.J.Carter, Esq., of the Bombay 

 Bfedical Service, who has done much towards the illustration of the 



geology of tin' Mast, as well as tin- elm illation of some of the obSGUrest 



points in animal and vegetable physiology. 



In our series of fossil DtUonida, which BOems to bfl rather North 



American than Asiatic, there are some prevailing features. All, 

 witli the exception "i I . Maleotmsoni, are characterized by an ombonal 

 ridge more or less prominent, and, with the exception of it and U, 

 imbricatus (both of which, from the nature of the matrix, possess i 

 verj indistind surface), are ornamented with beautiful small curved 

 furrows radiating from the apes of the umbo, and presenting their 



comave side towards its anterior margin. This kind of BCUlpture is 

 somewhat like that which is seen on [JnioS in the DoCCan at the 



present day; hut it never covers bo much of the beak, aor docs one 



of the curved rays ever unite with another so as to form the undula- 



