8 



SECOND YARKAND MISSION. 



tudinal striation however exists ; all the specimens, young and old, are without exception of 

 the peculiar thickness which suggested its excellent name of solidissima ; the five whorls 

 agree with those of Kohelt's original figure, which I suspect was taken from a Lake Pankong 

 specimen, and do not show the suhangulation described in the preceding ; the aperture is much 

 more expanded than in Kobelt's typical figure, which was evidently taken from a rather 

 young shell, the very thick columella in most specimens agrees with that of the type, but 

 in some few it is abruptly twisted back, as in pi. ii, fig. 21 of " Fedsch. Moll." (L. obliquata, 

 v. Mart.) 



These specimens are interesting as removing one of the few slight differences be- 

 tween L. obliquata andJD. solidissima ; my Pankong specimens clearly show the more expand- 

 ed aperture to be merely a question of age and condition, as is also the gradual slope of the 

 outer lip ; nearly all my specimens agree in this latter respect with typical obliquata, only 

 very few showing the angular outer lip of typical solidissima ; Kobelt in his description 

 pointed out the close affinity of the two forms, and also that L. obliquata must be classed 

 rather with L. lagotis, than L. auricularia ; the shortened columella seems to me the best 

 characteristic of the latter group, as shown in the form I have already described as a variety 

 of that species ; the difference is also excellently portrayed in von Marten's figures, pi. ii, 

 figs. 20 and 21, "Fedsch. Moll." The Pankong shell, though always preserving its chief cha- 

 racteristics, varies most remarkably, as will be seen from the accompanying measurements. 



The ordinary form : long. 22, diam. 17^ ; apert. long. 18, diam. 12| mm. 



A form with more produced spire and contracted aperture, agreeing with Kobelt's figure : 

 long. 22, diam. 15^ ; apert. long. 15 J, diam. 10J mm. 



A unique form, with quite depressed spire : long. 19, diam. 15| ; apert. long. 17 J, diam. 

 12 mm. 



A form (represented by six or seven specimens), with unusually expanded and more 

 rounded aperture : long. 18, diam. 17 ; apert. long. 14^, diam. 12 mm. 



About a hundred specimens from the shores of the Pankong Lake : both young and old 

 specimens show the same peculiar thickness of shell. 



LIMN.EA LAGOTIS, var. COSTTJLATA. 

 Limnaa lagotis, var. eostulata, v. Martens, Fedsch., Reise, Moll., pi. ii, fig. 24. 



More than a hundred specimens were collected by Dr. Stoliczka at Leh, agreeing exactly 

 with figs. 22 and 24 (loc. cit.}. I cannot consider the forms there figured as belonging to 

 even different varieties ; there are numerous individuals amongst the Leh specimens of all 

 the forms and of every conceivable connecting link ; the variety, as I understand it, appears 

 to be fairly constant as regards size and colour ; the spire, too, does not appear to vary much 

 more than in the figures quoted ; the columella, however, graduates from even a more rounded 

 shape than in figure 22 B to the straight (or slightly bent back) form of figure 24 A. 



Long. max. 18|, diam. 12 ; apert. long. 13f , diam. 8f mm. 



LIMN.EA LAGOTIS, var. YARKANDENSIS, nov. 



This is a striking and handsome form, close to the preceding, but half as large again, with 

 more produced spire 3 of five less convex whorls, much stouter texture and straighter, more 



