188 TESTACEOUS MOLLUSCA. 



cuticle yellowish, covered with green rays, nacre white ; cardinal 

 teeth small, the lateral long and straight. 1^ . . 1^. — Ohio. 



U. SuLCATUs. Lea. on U. I. p. 44. (^j- Tr. Am. PA. 3.) t. 8. 

 f. 12. — LJat. — Say. Am. Con. t. 5. — Rudibundus {female). Say. 

 Am. C. t. 5. — Eat. Subelhptic, short very thick, inequilateral, 

 ventricose, ventral edge incurved anteriorly by an oblique hollow 

 running from the beaks, which are nearly terminal obtuse eroded 

 and prominent; cuticle olive brown, wrinkled, with numerous fine 

 radiating hair-like lines, (except posteriorly), nacre purple : the 

 teeth large and double in both valves. l-rV • • ^to- — Ohio. 



U. Haysianus. Lea. Trans. Am. Ph. 5. t. 3. f. 7. Sub- 

 rotund, transverse, subventricose, scarcely thick, subequilateral, but 

 rather longer anteriorly, dentated at the anterior ventral edge, de- 

 pressed before the umbonal slope ; beaks thick and elevated : cuticle 

 yellowish brown, very smooth and shining, the rays obsolete, nacre 

 chocolate : cardinal teeth lobed, the lateral smooth and straight. 

 ^. . !•■ — N. America. 



U. Ellipsis. Lea. on U.l. p. 10. (cj- Tr. Am. 3.) t. A.f. 4. 

 — Eat. — Brevialis ? Sow. Elliptical, ventricose, very thick, 

 rounded at both ends ; beaks all but terminal, decorticated ; surface 

 somewhat wrinkled, the cuticle smooth and reddish brown, the 

 nacre pearly white and silvery, teeth large and well defined, the 

 cardinal crenulated. lyV • • ^t^o* — Ohio. 



U. Castaneus. Lea. on U. \. p. 101. (cj- Tr. Am. 4.) t. 11. 

 y*. 21. Obovate, transverse, thick, oblique, inequilateral, inflated, 

 rounded at both ends, ventral margin very convex, beaks prominent, 

 ligament short ; cuticle dark brown, becoming yellowish, with a few 

 rays anteriorly, nacre very pearly and irridescent : cardinal teeth 

 large, lateral short and straightish. ■^. . . 1. — M. Alabama. 



•f f f Oval. 



U. Tampicoensis. Lea. on U. 2. p. 24. (Sf Tr. Am. Ph.) 

 t. 7 .f. 18. Ovate, transverse, inflated, subcarinated, inequilateral, 

 thick, beaks somewhat prominent, ligament large and long: cuticle 

 blackish and ( apparently) rayless, nacre white and irridescent 

 (rarely rose colour) : cardinal teeth large, lateral long straightish 

 and large. 2| . . . A-^\. — Mexico. 



U. Lecontianus. Lea. on U. 2. j). 40. t. 12. /. 35. Ellip- 

 tical, transverse, inequilateral, somewhat inflated, thick, ventral 

 and dorsal edges straightish and subparallel, anterior side subbi- 

 angular ; beaks slightly elevated ; cuticle yellowish brown and 

 obscurely rayed, nacre pale salmon coloured, cardinal teeth small, 

 the lateral long and separate. 1^^^ . . 2^. — Georgia in America. 



U. Perdix. Lea. Trans. Am. Ph. 5. t. l\. f. 31. Trans- 

 verse, elliptical, inflated, thickish, anteriorly subangulated and 

 rather longer, ligamental edge straight, ventral edge entire ; beaks 



