94 



OBSERVATIONS. 



Many specimens of this shell was sent from New 

 Orleans in company with the declivis, Mortoni, pur- 

 puratus, &c, but the locality was not given. It has 

 some affinity with the subtentus, but is thinner in sub- 

 stance, and differs widely in the posterior angle. 

 It is never rayed, whilst that species has well marked 

 interrupted rays. Some specimens which are desti- 

 tute of the undulations on the posterior slope might 

 be confounded with U. complanatus. 



It is named in compliment to my friend William 

 Hembel, Esq., Vice-President of the Academy of 

 Natural Sciences of Philadelphia. 



END OF VOL. I. 



