PISIDIUM. 227 



Hab. Tonglu, Sikkim, at an altitude of 10,000 ft. ( \V. S. 

 Atkinson). 



The following note is appended to the description : " Com- 

 pared with P. bombai/amim this is a smaller, natter and less 

 inequilateral shell. . . ." 



Type in the British Museum. 



371. Pisidium nevillianum, Theobald. 



Pisidium nevillianum, Theobald, J. A. S. B. xlv, 1876, p. 188. 



Original description : Testa trigona, tumidiuscula, tenui, 

 inaequilaterali, postice modice convexa, antice elongata, sub- 

 acuminata, exilissime concentrice striata ; umbonibus tavigatis. 



Long. 3-50, lat. 3'60, diam. 2'20 mm. 



Nab. Near Burki. 



Appears to be chiefly distinguishable from its allies by its 

 trigonal form. 



372. Pisidium stewarti, Preston. 



Pisidium stewarti, Preatou, Rec. Ind. Mas., Calcutta, iii, 1909, 

 p. 116 (fig. in text). 



Original description : Shell sub-trigonal, rather inflated, pale 

 yellowish brown colour, marked with fine concentric lines 3f 

 growth ; umbones large ; anterior later.il teeth somewhat curved 

 with broad grooves between, posterior lateral teeth broad and 

 somewhat projecting in right, strong and sharply curved in left 

 valve. 



Long. 2-25, lat. 3 mm. 



Nab. High Hill, Grompa, Gyantse Valley, Tibet, in a small 

 stream, among moss and stones, 14,500 feet. 



The type-specimen is in the Indian Museum, Calcutta. 



Two specimens only were obtained by Capt. F. H. Stewart, 

 I. M.S.: its nearest ally would appear to be a fossil species from 

 the tertiary deposits of Belgium *, there being no known recent 

 form resembling it. 



373. Pisidium zugmayeri, Weber. 



Pisidium zuymai/cri, Weber, Zool. Jahrb. Jena, xxix, 1910, 

 pp. 310-311. 



Ori' final description: Testa flavescens, satis solida, insequilatera, 

 orbiculato-ovalis, parte posteriore abbreviata, obtusa, ventriosula, 

 tenuissime striata, sulcis post intervalla interpositis, lineis incre- 

 ment! signata ; umbones versus marginem posteriorem siti, rotun- 

 dati, prominuli ; dentes cardiuales valvae sinistrse bini, ante 

 umbones, superior (exterior) fere rectus, tennis, media parte 



* P. riticentianuni, B. B. Woodward, Cat. Brit. Spec. Pisidium in Co 

 rit.Mus., 1913, pp. 127-128. 



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