1854.] 



243 



Unio occidens Lea. Dated by Mr. Conrad, 1832? 



" rubiginosus Lea. " " 1832 



" heterodon Lea. " 1833 



" multiradiatus Lea. " 1832 



" securis Lea. " " 1832 



Unio acutissimus Lea. Dated by Mr. Conrad, Aug. 



1834 

 1832 

 1832 

 1832 

 1832 

 1832 

 1832 

 1832 

 1832 

 1832 

 1832 

 1834 

 1832 

 1832 

 1832 

 1838 



Unio ansjulatus Lea. Dated by Mr. Conrad, 

 subovatus Lea. 

 arcaeformis Lea. 

 pileus Lea. 

 tri^onus Lea. 

 subrotundus Lea. 



a 

 a 

 a 

 a 

 it 



< 



C Published in memoir 

 read before and depos- 

 ited with the Am. P.S. 

 March 6th, 1829, and 

 printed in Trans, v. 3, 

 p. 401. Distributed in 

 Mayor June 1829. The 



receipt of it, with com- 

 ments, is acknowledged 

 in a letter from Cincin- 

 nati, June 27th, 1829, 

 and it is noticed in Sil- 

 liman's Journal, vol.16 



ta 1829. 



Published in memoir 

 read before and depos- 

 ited with the Am. P.S. 

 May 7th, 1S30, and 

 printed in Trans, v. 4, 

 p. 63. Distributed in 

 the latter end of 1831, 

 and acknowledged by 

 correspondents as re- 

 ceived in that year. A 

 long review of this, 

 and the supplement 

 read May 20, 1831, ap- 

 peared in Silliman's 

 Jour, for Jan. Feb. and 

 March, 1832. It will 

 be observed that Mr. 

 Conrad makes three 

 dates for the species 

 described in this me- 

 moir, not one of which 

 is correct on his own 

 principle of the issue of 

 printed copies being the 

 time of date. This me- 

 moir and the follow- 

 ing supplement having 

 eighteen plates and 

 nearly fifty species, all 

 colored, required a long 

 time tofinish, hence the 

 delay between read- 

 ing the memoir and the 

 issuing of it complete. 

 Published in memoir 

 (supplement) read be- 

 fore and deposited with 

 the Am. Phil. Soc, 

 May 20th, 1831, and 

 printed in Trans, v. 4, 

 p. 105. This supple- 

 ment was issued with 

 the memoir. Therefore 

 all these dates of Mr. 

 Conrad's are one year 

 after the memoir was 

 distributed. 



20 



