326 BULLID/K. 



more obscure ones near the shoulder, none of them perceptible with- 

 out a magnifier ; aperture as long as the shell, narrow behind, and 

 widening forward ; outer lip simple and sharp, commencing beyond 

 the axis of the shell and rising a little, then turns and passes for- 

 wards by a regular curve ; the left margin is thickened and forms 

 a smooth, glossy pillar, which is twisted so as to form an oblique 

 fold ; at the base it terminates abruptly, so as almost to form an ob- 

 tuse tooth ; a thick callus, commencing at the junction of the outer 

 lip, runs round within the whorl, giving strength to the region of 

 the spire. There is no umbilical opening either at the tip or base. 

 Length three-twentieths of an inch, breadth one tenth of an inch 



Maine to Connecticut. 



Bulla oryza TOTTEN, Silliman's Journal of Science, xxviii, 1835, 

 p. 350, fig. 5. OLD., Invert. Mass. p. 168, f. 93. DE KAY, New 

 York Moll. p. 18, pi. 31, f. 327. Cylichna oryza STIMP., Check- 

 Lists p. 4. GLD., Invert. Mass. (W. G. B. edit.), p. 221, f. 512. 

 Tornatina (Cylichnella) oryza DALL, Rep. Gastr. p. 45. Haminea 

 oryza SOWB., Conch. Icon. f. 1. 



Family BULLID^ (Auct.) Pilsbry. 



Shell wholly external, globose, oval or oblong-cylindric, with 

 umbilicated vertex (rarely covered) and sunken spire, mottled color- 

 pattern and smoothish surface. Aperture as long as the shell, ris- 

 ing above the vertex, narrow above, dilated below ; columella simply 

 concave with reflexed crescentic callus and no fold. 



Animal capable of complete retraction into the shell, with a large 

 head-disc, truncated in front, bilobed behind, bearing eyes about in 

 the middle. No epipodial or parapodial lobes ; foot long, tapering 

 behind. Stomach containing three dumb-bell shaped horny plates. 

 (pi. 48, fig. 4). 



Radula having few longitudinal rows of teeth (formula 1-2'1'2'1), 

 the centrals transverse, bar-shaped with reflexed, multi-dentate cusp, 

 a submedian denticle smaller ; laterals two on each side, claw shaped 

 with numerous denticles. A cusp-less plate lies outside of the outer 

 lateral. (PI. 48, fig, 4.) 



This family, now for the first time separated from its rather dis- 

 tant allies the Akeridce, represents a very distinct line of differentia- 

 tion from the original Tectibranch stock with many longitudinal 

 rows of similar teeth. In the reduction in number of teeth, and the 



