36 CATALOGUE FAMILY UNIONIDyE. 



This is probably the most widely distributed Unio in North America. The 

 extreme northeastern stations, from which specimens have been seen, are the 

 Kideau canal and Ottawa river, Canada, near Ottawa. It ranges thence to west- 

 ern and central New York, to West Virginia. The most southwestern localities 

 reported are the San Antonio and San Saba rivers, in Texas. The most north- 

 ern localities authenticated by specimens are the Red river of the North, atPein- 

 bina, Lake Winnipeg, and Moose river, near Hudson's Bay, A depauperate form 

 was collected abundantly by Lieut. Beale, in Texas, which presents a greater de- 

 gree of variation than exists between many other Uniones known under various 

 specific names. A beautifully rayed variety, occurring in the Ohio, in northern In- 

 diana and in the smaller lakes of Michigan and Wisconsin was made the subject 

 of specific diagnosis by Mr. Anthony under the name of Unto distans. A more 

 cylindrical and somewhat larger form, common in Ohio. Illinois, Iowa and Kan- 

 sas, received from Mr. Barnes the name of Unio siliquoideus. The range of 

 variation which this species presents is more than paralleled by others which are 

 types of groups of wide distribution notably U. pustulosun, U. rubiginosus, 

 IT. undulatus, and U. complanatus. This last named form ranges from Nova 

 Scotia to southeastern Alabama, is peculiar to the Atlantic drainage, and is 

 known by some sixty names between these limits. It presents some of the 

 most remarkable synonomy in the whole family. In this, more than in any 

 other group of Uniones, perhaps, have species been multiplied by the exaggera- 

 tion of supeificial differences and by a failure to recognize the equally or more 

 apparent important resemblances. 



t Unio lyonii, Lea. 



(Jour. Acad. Nat Sei. Phila.,2nd Series, Vol. VI, PI. XXX 1 1, Fiir. 74.) 



This, a member of the nryenteus group, has been reported only from east 

 Tennessee. 



t Unio niaciilatiis, Conrad. 



(New Fresh Water Shells of the Tinted States, PI. IV, Fiff. 4.) 

 ''Elk and Flint rivers, tributaries to the Tennessee/' 



f Unio iiisustiis, Lea. 



(Trans. Am. Phi'. Sue., 2d Series, Vol. VIII, PI. XXVI, Fiy. (!;).) 

 ''French Broad river, east Tennessee." 



t Unio men kian MS. Lea. 



(Tnu s. Am. Phil. Sot;., Vol. VI. PI. XIX, Fi>r. ">J.) 

 This species, which is a member of the ligcLTtiintinux group, was described 



CATALOGUE 28 



