THE NAUTILUS. 



Vol.. XXVII. DECEMBER, 1913. No. 8 



TWO NEW SPECIES OF PARREYSIA FROM KAMERTTN, AFRICA. 



BY L. S. FRIERSON. 



PARREYSIA LOBENSIS n. sp. Plate V, lower figures. 



Sliell small, ovate. Epidermis dark brownish green, or olive, 

 shining on the disc, but dull on the post slope. Surface of the shell 

 densely covered with concentric, irregularly ziz-zag, sulcations, re- 

 sembling the beak sculpturing of such shells as Unio simonis Tris- 

 tram, giving a somewhat " dried-paint" aspect to the outer surface. 

 By transmitted light, dark blotches may be noted under the epider- 

 mis ; beaks badly eroded in the specimens seen, but probably high 

 and incurved. Nacre soft, orange, or pale yellowish pink. 

 Muscle scars of medium depth, nearly or quite confluent, lateral 

 teeth single in the right, double in the left valve. Cardinals are 

 much split up in both valves. Beak cavities deep, but not com- 

 pressed. Length 35, height 25, diameter 18 mm. Dimensions of a 

 cotype, length 32, height 25, diameter lo mm. The shell's chief 

 character is the sulcated aspect of its exterior, resembling in this re- 

 gard the Spatha kamerunensis of Walker, which accompanied this 

 shell. It shows a, distant kinship to P. hatittecceuri Bourg, but too 

 remote to be confounded with that species. It more nearly re- 

 sembles P. nyanyensis nobfs. It was collected in the Lobo River, 

 Kamerun, Africa, by Mr. George Schwab, Jan. 28, 1913, for the Mu- 

 seum of Comparative Zoology, Cambridge. Type No. 201 G 4. A 

 cotype is in my own cabinet. 



