490 l\v. H. B. Preston on new Shells 



A single female specimen from between Wau and Chak 

 Chak, in the Bahr-el-Gliazal Province, presented to the 

 British Museum by Mr. A. L. Butler. 



Tiiis snake appears to be most nearly related to 8. Chanleri, 

 described by Dr. Stejneger from a specimen in bad condition 

 obtained jit tlie mouth of the Tana River, British East Africa. 

 But the proportions of the head-shields and the coloration 

 are too different to justify me in referring the Balir-el-Ghazal 

 specimen to that species. 



LXIX. — Descriptions of neiv Species of Land and Fresh- 

 irater Shells from Central and South America. By II. B. 

 Pkeston, F.Z.S. 



FoHta 2)(ruviana, sp. n. (Fig. 1.) 



Shell somewliat depressed, thin, pale brownish horn- 

 colour ; whorls 4^, sculptured witli transverse, arcuate striae ; 

 sutures deeply impressed ; umbilicus wide and deep ; peri- 

 stome simple ; aperture lunate. 



Alt. 3'25, diam. mnj. 7*25 mm. 



Aperture: alt. 2, diam. 1"5 mm. 



Ilab. Chanchamayo, Peru. 



Closely allied to P. insignis, D'Orb. *, wliich occurred with 

 it ; P. ptruviana is, however, not so depressed and of a darker 

 colour, the umbilicus is also rather narrower and the sutures 

 though well defined do not present the almost channelled 

 appearance which is the case with P. insignis. 



Stephanoda bogotensisy sp. n. (Fig. 2.) 



Shell orbicular, somewhat depressed, dark brown, showing 

 traces of having been covered with a hairy periostracum ; 

 whorls 5^, sculptured with tine, arcuate, transverse, and very 

 minute spiral striae; umbilicus very wide and deep ; aperture 

 lunate. 



Alt. 4, diam. maj. 8 mm. 



Aperture: alt. 2*5, diam. 1 mm. 



Ilab. Bogota, United States of Colombia. 



Pleurodonte (Labgrinthus) Da Costiana, sp. n. (Fig. 3.) 



Shell thin, subdepressed, carinate, pale brownish horn- 

 colour; whorls 4i, obliquely striate with lines of growth and 



* Yov. Am&-. U6nd. t. 2(5. ff. 14-17. 



