256 SCAPHANDER. 



The type of this group is a pliocene fossil of Piedmont in which 

 the callus is plicated. Fig. 34 shows the front view, fig. 33 a dorsal 

 view with the body- wall removed to show the internal continuation 

 of the spiral callus. Bulla grandis Seguenza (Form. Terz. di Reg- 

 gio, p. 250, pi. 16, f. 4, 1880) is another fossil species of the same 

 group. In the recent fauna it is known only from deep water in 

 the Antillean district. 



S. BATHYMOPHILA Dall. PL 32, figs. 27 (adult) and 28 (young). 



Shell large, stout, white, polished, sculptured with numerous 

 puncticulate stria3, crowded toward the ends and few and distant in 

 the middle ; outer lip extending backward a short distance from the 

 spire, then sweeping downward, forward, outward, and then up- 

 ward, curving downward and backward again to join the subtruncate 

 columella, above and behind which there is almost a canal; col- 

 umella reflected, with a tolerably thick callus, but no umbilicus or 

 umbilical chink ; body with a thin deposit of callus (in one instance 

 much thickened and roughened, apparently by disease) ; aperture 

 very narrow behind, very wide and somewhat oblique in front ; 

 lines of growth on the surface hardly visible. Lon. of shell and 

 aperture, 16*5; from summit to oblique truncation of columella, 

 13'75. Max. lat. of shell, 11*25 ; of aperture, 7'0; min. lat. of 

 aperture, I/O mill. (Dall). 



Alt. 31, diam. 24 mill. 



In young specimens 3*5 mm. long there are three and a half 

 whorls ; the nucleus is visible turned on its side and half immersed ; 

 it is heliciform, translucent white and minute ; the striation is more 

 uniformly distributed over the shell and is exceedingly fine ; the 

 nucleus (but not the whorls outside of it) remains partly visible 

 until the shell has attained a length of 8'25 mm. Like most young 

 shells of this group the young are more pointed before and behind, 

 and less expanded than the adult. 



100 miles east from Delaware Say, 554 fms. ; Fernandina, 

 Florida; Yucatan Strait, 640 fms. ; east from Tobago, 880 tins. 



Atys ? bathymopkila DALL, Bull. M. C. Z. ix, p. 98, IS&LSab- 

 atia bathymophila DALL, Amer. Nat. xvi, 1882, p. 884 ; Blake 

 Oastr., p. 53, pi. 17, f. 9, 96; Proc. U. S. Nat. Mus. xii, p. 298, 

 1889. 



