DKS MOINKS ATADKMY OF SCIENCE. 47 



f Unio recnrvatns. Lea. 



!<>hs( rxiitions oil the (Jeinis I'nio. \'ol. XHI. PI. II, Fig. 6.) 



Tennessee and Holstoii rivers, above Tuscumbia, Alabama. This is a mem- 

 ber of the <'I>cintx group, and piobably synonymous \vith I', ijlohntns and U. 

 xiilnjlulHrtiix. which see. 



{: Unio rcevianus, Lea. 



(Trans. Am. Phil. Soc.. id S rles, Vol. X, PI. XX, Fiji- 2K.) 

 lied river, at Alexandria, Louisiana. A member of the Intcolus group. 



f Unio regiilaris, Lea. 



(Trans. Am. Phil. Soc.. ;,'d Series, Vol. VIJI, PI. XXV. Fig. ^U 

 "French Broad river, east Tennessee." 



t Unio rctustis, Lamarck. 



(Figured '.') 

 Oliio to Illinois in tlu 1 Mississippi river: south to the Holstoii river, Tennessee. 



tl.'nio rotundatiis, Lamarck. 



(Figured ':) 



'I'lie only specimens \\hicli have come under notice were from Louisiana. No 

 authentic record of this form, vero, is known outside that state, though Lea 

 credits it to the Ohio river. (Synopsis of the Family Unionidje, 4th Ed. P. 100.) 

 While this is a true I'nio it lias a greater resemblance to a very large Cyr< ha 

 than to any other familiar shell. The epidermis is velvety and jet black. Con- 

 rhologists appear to have confounded oval forms of U. ebtnus, of the Ohio 

 drainage with Lamarck's species, which is unique among American 1'ninniiltr. 



* Unio nilriu'iiiosiis. Lea. 



(Trai.s. Am. Phil. Snc., Vul. III. PI. VIII, Fig. 10.) 



Kanges from central New York, in the Erie Canal at Mohawk, to Jackson. 

 Mississippi ; to Trinity r.\ er. Texas : north to Indian Territory, Kansas : Nebraska ; 

 lo Minnesota and Wisconsin. There is a very instinctive synonomy in the group 

 which this species typilies embracing, among others, J'. rabid nx, I'. /H(////.y, 

 r.cluinii I', riddcllii and I'. <-lii<-kx<tirrnxix. This species is a very varia- 

 ble one due probably to the diverse physical conditions imposed by its extensive 

 distribution. It is usually a very abundant species. 



c \r.u.o<;rK 39. 



