188 THE NAUTILUS. 



NEW SPECIES OF ANCYLID.E. 



BY BRYANT WALKER. 



Ancylus (Ferrissia) hendersoni n. sp. PI. ix, figs. 8-10. 



Shell small, thin, delicate, oval, slightly wider anteriorly, right 

 side nearly straight, left side regularly curved ; obtusely elevated ; 

 light horn-colored, apex very obtuse, depressed, not projecting above 

 the normal outline of the shell, and only slightly deflected toward the 

 right; apical pit in the centre and looking upwards; apical striae 

 strong and regular, originating from the circumference of the apical 

 pit and projecting down towards the whole upper surface of the shell, 

 becoming lighter and more irregular below, comparatively few reach- 

 ing the edge of the shell; lines of growth irregular, but rather strong, 

 giving a reticulated appearance to the surface where they cross the 

 radial striae ; anterior slope, especially above, very convex, the high- 

 est point of the shell being in front of the apex ; posterior slope 

 slightly concave, nearly straight ; left lateral slope convex, right 

 slope nearly straight. 



Length 2.5, width 1.5, alt. .75 mm. 



Type (No. 25707 Coll. Walker) from Lake Waccamaw, N. C. 

 Cotypes in the collections of Messrs. Jno. B. Henderson, Jr., and G. 

 W. H. Soelner, of Washington, D. C. This small species was found 

 by Messrs. Henderson and Soelner in the pools of the swampy woods 

 around the shore of Lake Waccamaw in the fall of 1906. 



It is well characterized by its obtusely elevated shape, blunt apex 

 and radiating ribs or striae. In sculpture it resembles A. borealis 

 Mse., but differs from its thin, delicate shell, smaller size and differ- 

 ent proportions, being relatively less elevated and with a longer and 

 more sloping posterior outline. 



Ancylus (Ferrissia) novangli^e n. sp. PI. ix, figs. 5, 6 and 7. 



Shell small, depressed, elongate oval, sides nearly parallel, the 

 left being slightly more curved than the right ; regularly rounded at 

 the extremities; apex prominent, bluntly rounded, situated on the 

 posterior third, very eccentric, turned decidedly to the right, apical 

 striae prominent ; lines of growth fine and regular ; anterior slope 

 long, convex with numerous, fine, radiating ribs, which extend to 

 the periphery ; posterior slope oblique, nearly straight below the 



