I I 24 r'ARRF.YSIA 



Aciiticosta trisiih'ata Haas, Conch. Cab., Unio. 191 2, pi. 30, 



fig. II. 



T know nothing' whatever of this species and am very doubt- 

 ful whether it is related to P. corbis at all. The three sub- 

 concentric ridges on the umbonal region are characters not 

 found in any other species T have placed in Parreysia and if 

 they are a part of the beak sculpture they would indicate that 

 this shell belonged in the Kxobranchia\ Heude states, however, 

 that the beaks are eroded. The general form of the shell as 

 indicated by his figure would seem to ally it with the forms 

 T have first described. 



Group of Parreysia leopohi^illcitsis. 



Shell rounded rhomboid, somewhat inflated, subsolid, with 

 a rounded post-ridge ; beaks full, the sculpture strongly and 

 regularly zigzag-radial and extending well over the body of 

 the shell ; pseudocardinals heavy, subcompressed, crenate ; an- 

 terior scars deep. 



Parrkysia lkopoldvillknsis (Putzeys). 



Shell irregularly obovate or subtriangular, subsolid, subin- 

 flated, somewhat inequilateral ; beaks small but decidedly ele- 

 vated, sculptured with radiating ridges on the posterior slope 

 and M'ith chevron-shaped markings below them, this sculpture 

 extending over a considerable part of the surface ; posterior 

 ridge scarcely developed ; dorsal line curved from the upper 

 part of the narrow^, rounded anterior end to the hinder end of 

 the small wing ; the posterior end is obliquely and somewhat 

 roundly truncated, the truncation ending in a rounded point 

 near the base of the shell ; pseudocardinals rather strong, sub- 

 compressed, crenulate ; laterals lamellar, curved ; anterior scars 

 impressed ; nacre pearly, bluish, salmon-tinted in the cavaties. 



Length 45. height 28-30. diam. 15-19 mm, 



Stanley Pool, Leopoldville, Congo. 

 Unio leopoldinllensis Putzeys, Proc. A^erb. Soc. Mai. P>elg.. 



XXVII, 1898. pi. xxvii, figs. 12. 13. 

 Parreysia JeopoJd^HIcusis Smrsox, Syn., 1900, p. 846. 



