28 



U N I O . 



III. SUBGENUS UNIO. 1 



TRIANGULAR. 



*Cumingii. Lea. 



Unio Cumingii. Reeve? (No. 264.) 



gigas. Swain. Lea. 

 Me/jadomus gigas. Swain. 



*Nicklinianus. Lea. Han. 

 *eximius. Lea. Mart. 

 *Boykinianus. Lea. Chenu. 



*inflatus. Lea. Kust. Han. 



Symph. inflata. Lea, in Trans. Am. 



P. S. 

 Unio Alabamensis. Con. 



*delphinus. Grun. Lea. Kust. Chenu. 



*alatus. Say. Lam. Swain. Bar. 



Hild. Menke. Adams. Kust. 



Dekay. Potter. Deshayes. Con. 



Sow. Chenu. Han. 

 Mya alata. Wood. Eat. 

 Symph. alata. Lea. Sh. & Eat. 

 Lymnadia alata. Sow. Swain. 

 Metaptera alata. Stimpson. (Agass. 



MSS.) 



*Heermannii. Lea. 



TRIANGULAR. 



*Hainesianus. Lea. Mart. 

 Unio imperialis. More. 



subtrigonus. Soiv. 3 



*superbus. Lea. 



Unio macropterus. 4 Dunk. 

 Unio velaris. Bens. 



*gravidus. Lea. Mart. 

 Unio alnormis. More. 



*delpkinulus. 5 More. 



*la3vissimus. Lea. Adams. Han. 

 Symph. Isevissima. Lea. Sh. & Eat. 



Swain. 

 Unio isevissima. Deshayes. 



*Myersianus. Lea. 



Ortonii. Lea. 

 *Housei. Lea. Mart. 



*gracilis. 6 Barnes. Hild. Desh. Han. 



Adams. 



Unio planus. Barnes. 

 Unio fragilis. Swain. Kust. 

 Symph. gracilis. Lea. Sh. & Eat. 



1 Retzius, Nova Testaceorum Genera, 1788. 



' Judging from the figure of Reeves, I should think it had been taken from Marg. complanata, Barnes. 



8 The figure is very much like that of Hainesianus, Lea, and may be a half grown specimen. 



4 Dr. Bunker received it from Danu-Luar River, Sumatra. 



6 A well-characterized species from Honduras. 



6 Mr. Swainson's description of fragilis appeared in his Zool. Ill, dated 1822-1823; and Mr. Barnes's 

 in Silliman's Journal for April, 1823. As I do not know which really was issued first, I have preferred 

 to give preference to Mr. Barnes's name, by which the shell has been universally known among our con- 

 chologists. 



