PLANORBIS BICARINATUS, Say. 



Plate 1.— Figs. 1—6. 



P. testa utrinque ad periphcriam angulata: superne late 

 umbilicata, subtus valde depressa: anfractilHis tribus fusco- 

 lutescente. 



SYNONYMS AND REFERENCES. 



P. BICARINATUS, Say. Nich. Encyc. (Amer. ed.) art. 



Conchology, No. 2, pi. i. fig. 4. — American Conchology, 



pi. 54, fig. 3. 

 Helix angulatus, Rackett. Lin. Tr., xiv. pi. 5. fig. 1. 



" " Wood's Cat. supl., pi. 7. fig. 12. 



P. BICARINATUS, Sowerby's Genera, fig. 4. 

 P. ENGONATUS, CoN. New fr. w. shells, pi. 9, fig. 8. 

 P. BICARINATUS, GouLD. Invert, of Mass., p. 203, fig. 134. 

 Helisoma bjcarinata, Swainson. Malac, p. 337. 



DESCRIPTION. 



Animal with variable tentacles, which are 

 very long upon some individuals, and shorter 

 upon others; sometimes they are of different 

 length upon the same individual; the general 

 color is yellowish-brown, spotted with whitish 

 or yellowish dust-like dots, forming short lines 

 along the sides of the head, extending back- 



