132 PROCEEDINGS OF THE ACADEMY OF [1892. 



Arconaia Provancheriana Pilsbry, PI. \'ir, figs. 4, 5, 6. 



This species has already been briefly noticed in these Proceedings, 

 and a description has been published in the " Xautilus, " IV, p. 127. 

 It may be compared in the degree and direction of twist to the 

 variety of Arconaia contorta Lea, figured by Heude on PI. XV, fig. 

 32, of his " Conchyliologie fluviatile de la Province de Nanking et 

 de la Chine Centi-ale, " a Chinese species. The locality of this 

 species is not known positively, but it is supposed to be from China. 

 The type is No. 63,094 of the collection of the Philadelphia 

 Academy. 



The Arconaia Delaportei of Crosse and Fischer (Journal de Con- 

 chyliologie, 1876, Pis. X and XI,) differs decidedly from the present 

 form in outline, and in the winged extremities. A. Provancheriana 

 may, indeed, prove to belong elsewhere than in Arconaia, as it is 

 not at all produced at the ends, as are the species hitherto in- 

 cluded in that genus or subgenus. 



