56 
Records of the Geological Surrey of India. 
[vol. VI. 
refer to Mr. Blanford’s contributions to Indian Malacology in the Journal As. Soc., 
Bengal, for 1866, page 134, which contain a highly useful and condensed paradigm of 
our Indian Uniones. 
Mr. Blanford is undoubtedly correct in saying that “ both Lamarck’s and Chemnitz’s 
types (of Corrugatus) are quite distinct from Benson’s U. favidens, which has been confounded 
with them,” but with a very large series before me, I consider that this distinction is a 
racial one, not a specific one. 
If the rules of priority would have permitted it, I should have preferred, as the more 
natural course, to have taken Benson’s IJ. favidens as the type of that species round which 
so many races or sub-species cluster; but as this cannot be, U. favidens must stand as a 
race perfectly separable, but still only- a race of the wretched, ill-nourished U. corrugatus, 
Mull., for the*epithet “ tenera ” applied to any of the forms of this robust species, stamps it 
as an abnormal individual, impoverished by unfavorable local conditions, and subjected to 
deficient or imperfect alimentation. 
That the utmost diversity exists between the races which I unite under IJ. corrugatus 
may well bo, since without pretending to anything like a complete knowledge of all the 
forms of this species throughout its entire Indian range, there must still be admitted sixteen 
separable races, exhibiting very variable degrees of difference from each other; even after 
excluding U. Icevirosiris of Benson as a synonym of U. JVagporensis, Lea, and uniting 
1Yagporensis, Lea, with Wynegungensis, Lea, with which it is essentially identical, or too 
trivially distinct to be separated, judging from a large series of both forms. 
U. COEETTGATTTS, Mull. 
1. Var. triembolus, B. 
This form occurs very fine, both living and fossil, in the Narbadft. 
A fossil specimen measures— 
Breadth ... ... ... 66 | 
Length ... ... ... 40 Mills. 
Thickness ... ... ... 26; 
and I have no living specimen which quite attains these dimensions. 
2. Var. Wynegungensis, Lea. 
A stout trigonal and elongate form, which approaches the U. lasvirostris, B., seems 
equally common with the last, and passes into it. 
A fossil specimen measures— 
Breadth ... ... ...73) 
Length ... ... ... 39 ,> Mills. 
Thickness ... — ... 27 .1 
And in this case also I have no living specimen which equals these dimensions, my largest 
specimen of this type from the Kistna only reaching 60 mills. 
3. Var. Indica, Sow. 
This well marked form occurs both living and fossil; one of the last collected by 
Mr. Hacket measuring— 
Breadth ... ... ... 30) 
Length ... — ••• 27 > Mills. 
Thickness ... ... ••• 19 ) 
This is not a large race, as a fine recent specimen from the Narbada only measures 
41, 34, 21 mills. It is mainly confined to the Narbada, though I have it also recorded 
from Bajputana. 
