28 



UNIO. 



III. SUBGENUS UNIO.' 



TRIANGULAR. 



*Cimiingii. Lea. 



Unio Cumingii. Reeve? (No. 26-i.) 



gigas. Sioain. Lea. 

 Megadomus gigas. Sivain. 



*Nicklinianus. Lea. Han. 



*eximius. Lea. Mart. 



*Boykinianus. Lea. Chenu. 



*mflatus. Lea. Kust. Han. 



Symph. inflata. Lea, in Trans. Am. 



P. S. 

 Unio Alalamensis. Con. 



*delpliiniis. Grun. Lea. Kust. Chenu. 



*alatiis. Say. Lam. Swain. Bar. 



Hild. Menhe. Adams. Kilst. 



Dekay. Potier. Deshayes. Con. 



Sow. Chenu. Han. 

 Mya alata. Wood. Eat. 

 Symph. alata. Lea. Sh. & Eat. 

 Lymnadia alata. Sow. Swain. 

 Metaptera alata. Stimpson. (Agass. 



MSS.) 



*Heerniarmii. Lea. 



TRIANGULAR. 



*Hainesianus. Lea. Mart. 

 Unio imperialis. More. 



subtrigonus. Soiv.^ 



*superbus. Lea. 



Unio macropterus.^ Dunh. 

 Unio velaris. Bens. 



*graviclus. Lea. Mart. 

 Unio almormis. More. 



*delpliinulus.' More. 



*l£evissinius. Lea. Adams. Han. 

 Symph. leevissima. Lea. Sh. & Eat. 



Swain. 

 Unio leevissima. Deshayes. 



*Myersiaiiiis. Lea. 



Ortonii. Lea. 



^Housei. Lea. Mart. 



*gracilis.^ Barnes. Hild. Desh. Han. 

 Adams. 

 Unio planus. Barnes. 

 Unio fragilis. Siuain. Kilst. 

 Symph. gracilis. Lea. Sh. & Eat. 



' Retzius, Nova Testaceorum Genera, 1Y88. 



= Judging from the figure of Eeeves, I sliould think it had been taken from Marg. complanata, Barnes. 



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



* Dr. Dunker received it from Danu-Luar River, Sumatra. 

 ^ A well-characterized species from Honduras. 



* Mr. Swainson's description of fragilis appeared in his Zool. 77Z., 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. 



