MOLLUSCA 01' INDIA, 131 



lunate, broader than high. Peristome not sharp, slightly wavy, 

 with a very slight white thickening inside, the basal margin curved 

 forward, the columella scarcely reflected. 



" Major diameter 0*67, minor 0'62, axis 0*3S inch. 



" The above is the typical form ; but there is a smaller variety, 

 depressedly turbinate in shape, with the spire conical, measuring 

 0'55 inch in its major diameter and 0'36 in height. This form 

 passes by insensible gradations into the type. 



"The shell represented in the ' Conch ologialndica' is intermediate 

 between the two varieties here described and figui'ed ; the apex in 

 the ' Conchologia ' figure is more prominent and blunt than in the 

 specimens now before me. These were procured from the Naga 

 Hills, south of Gola Ghat, Assam, by Mr. Masters in 1859 ; other 

 specimens were subsequently found on the Garo, Khasi, and Naga 

 Hills by Colonel Godwin-Austen. The shells from the Khasi Hills 

 have the filiform costulation on the upper surface finer and less 

 regular than those from the Assam side of the Naga Hills. In 

 Khasi shells 2, 3, or 4 ribs occur at nearly regular intervals, and 

 then a rib appears to be omitted ; this is not the case with those 

 from Upper Assam. 



'* The species scarcely differs from E. ornatissima, found on the 

 other side of the Brahmaputra Valley, at the base of the Sikkim 

 Hills, except in being imperforate ; E. climacterica, of which Mr. 

 Nevill considers the present shell a variety, is always sharply 

 keeled at the periphery. The two forms may pass into each other, 

 but I have aever seen any intermediate links ; and as they differ 

 from each other much more than E. vidua does from E. ornatissima, 

 or E. climacterica from E. austeni, it is better to have distinctive 

 names for them. 



" I am indebted to Colonel Godwin-Austen for the following note 

 on the animal of A. vidua observed at Cherra Poongee, Khasi 

 Hills :— 



'"Animal of a neutral grey tint about the neck and eye-tentacles, 

 which are rather long and fine ; the oral tentacles are also of a 

 dark tinge. Extremity of foot truncated, with mucous gland. 

 Body long and thin. No tongue-like processes on the mantle 

 observed.' " 



The following is my description, in the same paper, of the teeth 

 in E. climacterica : — 



" Median tooth tricuspid, the central point very long, the lateral 

 cusps very small. The first 14 laterals are long and broad, with a 

 single short small cusp on the lower outer margin ; the 25 outer- 

 most are long and narrow, curvilinear, bicuspid, the outer point the 

 shorter, being less than half as long as the inner. Jaw slightly 

 curved, the front edge a little convex. 



" The number of teeth in a row is apparently 79. A sketch 

 shows that the form of both central teeth and laterals is very similar 

 to that of E. siihopaca.^' We now know that this is the form of the 

 central teeth common to all the genera of the Zonitidae, with modi- 

 fication in some of them. 



