I I 26 PARRlvYSlA 



shell and he gives as its greatest length 43 millimeters. The 

 early sculpture of this form is excessively strong. Adams' 

 type was probably a young specimen. 



Parreysia STUHi^MANNi (vou Martcns). 



Shell irregularly elliptical, somewhat inflated, shining, 

 brown, inequilateral ; beaks very high, with strong zigzag- 

 radial sculpture, which extends to some distance out on the 

 disk, the outer part of the shell being nearly smooth; anterior 

 end rounded ; base line curved ; hinge line lightly curved, ang- 

 led at the hinder end of the ligament ; dorsal slope obliquely 

 truncate ; posterior ridge rather high, ending in a rounded 

 point below the median line ; nacre silvery white. 



Length 43, height 26, diam. 14 nmi. 



Albert Edward Lake, Central Africa. 

 Unio stuhlmanni von Martens, Besch. Deuts. Ost-Af., 1897, 



p. 231, pi. viT, fig. 13. 

 Parreysia stuhhuanni Simpson, Syn., 1900, p. 846. 



In outline this shell resembles certain specimens of Plagiola 

 donariformis. The characteristic beak and earlier sculpture 

 does not appear to come very far out over the surface. 



Parreysia HAUTTF.coiuRi ( Bourguignat ) . 



Shell irregularly oval, subinflated, rather solid, inequilateral ; 

 bpeaks moderately full and high, with strong, zigzag sculpture, 

 which extends over the shell nearly to its border ; beyond this 

 the border is concentrically striate ; anterior end rounded ; base 

 line curved, with a tendency to be slightly produced in the 

 middle ; outline of dorsal slope arcuate ; posterior ridge full, 

 narrowly rounded, placed near to the upper edge of the shell, 

 ending in a rounded point a little below the median line ; 

 epidermis uniform brown-olive ; nacre bluish ; pseudocardinals 

 compressed, triangular, elevated ; laterals thin. 



Length 36, height 22, diam. 16 mm. 



Lake Victoria Nyanza, Central Africa. 

 Unio hanttecceuri Bourguignat, Moll. Ny. Ouk., 1883, p. 5, 



figs. 1-3. — VON Martens, Besch. Deuts. Ost-Af., 1897, p. 



232, pi. I, fig. 23 ; pi. VII, fig. 3. 

 Nodularia hmittecwuri Simpson, Syn., 1900, p. 846. 

 Unio i^rantianiis Bourguignat, Moll. Ny. Ouk., 1883, p. 14. 



