THE NAUTILUS. 99 



13. Macgillivrayi Group. 



P. macgillivrayi Pfr. P. turricula Pse. 



P. caledonica Pfr. P. radiolata Pfr. 



P. carnicola Hartm. P. eburnea Hartm. 



P. paterna Hartm. P. proxima Hartm. 



P. eximia Hartm. P. pyramis Hartm. 



P. albescens Hartm. P. auraniana Hartm. 



P. alabastrina Pfr. P. compressa Pfr. 



Subgenus Diplomorpha Ancey. 



The jaw, lingual dentition and genitalia are like Partula. The shell 

 does not possess spiral stripe. 



D. layardi Braz. D. delatouri Hartm. 



D. coxi Hartm. D. peasei Cox. 



BIFIDARIA; A NEW SUBGENUS OF PUPA. 



BY DE. V. STERKI, NEW PHILADELPHIA, OHIO. 



In the " Preliminary List of North American Pupidse " ^ the name 

 of this subgenus has been published, but without further note except 

 that it was in my mss. for a few years. Since then I have obtained 

 other species belonging to it, and became more and more convinced 

 that it is really a natural group, and one of the richest in species. 



The forms ranging under it are small, few exceeding 3 mm. of 

 altitude (P. armifera Say, hunana Grdl.). In shape they are rather 

 various ; cylindric, turriculate, conic, ovoid. The color is a lighter 

 or deeper horn, to chestnut on one, to colorless, i. e. whitish or 

 glossy-albino on the other side ; in some the coloration is rather con- 

 stant while others show all these variations, e. g., P. hordeacea Gabb. 

 The surface is smooth, polished, or finely striate or, though rarely, 

 with fine ribs ; heavily ribbed forms have not come to my notice. 

 A prominent feature lies in the formation of the apertural lamellEe, 

 or plicae, especially in the one on the parietal wall ; it is (with few 

 exceptions) large and more or less distinctly complex, designated in 

 the descriptions as " complex, twisted, bicuspid, bifurcate, emarginate. 



1 The Nautilus, VI, p. 4 and 7. 



