60 



LAND AND FRESBWATER 



Glessula (Rishetia) stjndeki, n. sp. ] 



Locality. Amin Gaon, Gowliathi, Assam. Only one example 

 {Sander Lall Hoi-a). Type in Indian Museum, Calcutta. 



Shell very elongately turretcd ; sculpture : smooth to eye, rather 

 distant striation in low relief, the first two embryonic whorls 

 smooth ; colour pale umber-brown ; spire long, very regularly 

 tapering, apex fine; suture well impressed; whorls 14-, sides fiatly 

 convex, proportion of last whorl to length, 100 : 32-o ; aperture 

 narrowly ovate ; peristome simple, thin ; columellar margin 

 concave, sharply truncate. 



Size: maj. diam. 9'0 ; alt. axis Wo mm. 



This is a beautiful and new species, the single specimen is in 

 most perfect state. Its nearest ally is G. haculina, Hy. lihuidford, 

 of Darjiling, compared with which it differs in its greater length 

 and number of whorls, 14 to lc5, and general tumidity, more 

 convex whorls, with suture more impressed, sculpture not so full, 

 side of spire not so straight and flat, last whorl larger and more 

 swollen. 



Compared with G. suhaculina, G.-A., of the Khasi Hills and 

 South Jaintia, another near ally, it differs considerably as follows: 

 It is much longer, 14 whorls to 12, length 41 to 34-75 mm.; more 

 alternate with finer apex ; tapering very regularly, side of spire 

 quite straight : sculpture far less pronounced; columellar margin 

 shorter and with more convexity. Considerable interest is attached 

 to the finding of this Ghssula at Amin Gaon. 4(i0 yards from the 

 llailway Station, where Sunder Lall of the Indian lluseum, 

 returning from Munipur, was detained for six hours ; he made the 

 best of the opportunity, obtaining at the same time six specimens 

 of another Glessula, a variety of sarissa. 



Regarding tlie range of 6r. baculiiui. it is of interest; 400 miles 

 east of Darjiling, at the base of the Dafla Hills, 450 feet, I found 

 tliat G. harmutliensis took its place ; the apcc is more obtuse and 

 the sculpture is very different from that of Hy. Blan ford's 

 species. It comes from a low elevation compared with Darjiling ; 

 Harmutti is some 150 miles east from Gowhathi ; 50 milts north 

 of that place, near Dewangiri, at the base of the Bhutan Hills, 

 the Datta species, or one very close to it, in all probability is' 

 to be found, indicative of the area and side from which G. sunderi 

 was derived. The intrusive granite at (iowhathi extends thence 

 for some distance north, exposed and rising at intervals above 

 the deep alluvial of the Bramaputra, which evidentl}' covers 

 much more, pointing to a once close connection of low liilly 

 country, by which land-moUusca could travel far out into the 

 plain of Assam. Such former connection with the Assam Kango 

 or the Khasi and Garo Hills is more pronounced between Gowhathi 

 and Dubri, trending towards the great mass of granite of Gipmochi 

 Peak into the Western Bhutan Hills (see also page 11). 



