902 



MOLLUSCA. 



of the varieties of Z7. cceruleus, Lea. It is easily distinguished from TJ. honneaudi 

 by its more irregular shape, thinner texture, by the acute angulation, greater pro- 

 duction posteriorly, and by the more developed sculpture ; a constant character also 

 is the pink colour of the nacre, which in U. honneaudi is bluish- white ; this is 

 equally distinct and characteristic in young as in old specimens. 



Type from Myadoung ; long. 32, lat. 15J, crass, llf mm. 



Specimen of Z7. honneaudi from Myadoung ; long. 31, lat. 18, crass. 13 mm. 



-Family— CYBUNID^. 



Genus Corbicula, Meg. 

 CouBicuLA LAMARCKiANA, Prime. 



Corhicula lamarcUana, Prime, Ann. Lye. N. York, 1867; Nevill, I. c, p. 40. 



Specimens obtained at Hot ha and Momein (5,500 feet) in Yunnan, and also at 

 Mandalay, agree exactly with Prime's original figure. Lieutenant- Colonel Godwin- 

 Austen also found a small form of this well-marked species at Manipur, in the 

 Kuchai stream. 



Long. 28J, lat. 20J, crass. 13 mm. 



COEBICrLA YUNNANENSIS, Nevill. 



Corhicula yunnanensis, Nevill, Jom^n. As. Soc., Bengal^ vol. xlvi, 1877, p. 40. 



Medium-sized specimens from Yaylaymaw agree fairly with Prime's figure and 

 description of C Unneana,^ the principal difference being the less truncate anterior 



Fig. 32. 

 Corhicula yunnanensis, nat. size. 



side. Shell large, thick, transverse, inequilateral, compressed, rather abruptly tumid 

 towards the umbones; anteriorly moderately produced and rounded, posteriorly 

 produced and truncate (exactly as in Prime's figure of C. linneana) ; lateral teeth 

 curved, the anterior a little more so than the posterior ; no lunule ; epidermis dark 

 brown, strise regular and close ; interior violet, of a darker shade near the margin. 



1 Ann. Lye. N. York, 1867. 



