272 ORTMANN— CORRELATION OF SHAPE AND 



Group of Fusconaia subrotunda in the Upper Ohio System. 



The following is the taxonomy of this group here accepted. 



1. Fusconaia subrotunda (Lea). — Dia. 50 per cent, of length 

 and over. 



Unio subrotundus Lea. '31 (Ohio). — Quadrula subrotunda Simp- 

 son, '14, p. 892.^ 

 Dia. (Lea) : 60 per cent. Simpson gives: 44, 49, 51 per cent., 



but only the last one would belong here according to the definition 



accepted above. 



Unoi politiis Say, '34. — Synonym to siihrotunda according to 

 Simpson. 

 Dia. (Conrad, '■^y) : 53 per cent. 



Fusconaia leucogona (pars) Ortmann, Nautil. 27, '13, p. 89 (Elk 

 River, W. Va.). 



2. Fusconaia subrotunda kirtlandiana (Lea). — Dia. less 

 than 50 per cent. 



Unio kirtlandianus Lea, '34 (Mahoning R., Ohio). — Quadrula kirt- 

 landiana Simpson, '14, p. 891. 

 Dia. (Lea) : 44 per cent.; (Simpson) : 33, 38 per cent. 



Fusconaia leucogona (pars) Ortmann, 1. c. 



Measurements taken from My Material}^ 



Loc. No. Max. Min. Av. 

 Ohio River. 



Portsmouth 5 67 51 59 suhrot. 



Portland 4 52 49 51 subrot. (kirtl.) 



Parkersburg i 51 51 51 subrot. 



St. Mary's 8 62 50 54 subrot. 



Toronto 2 52 50 51 subrot. 



Cooks Ferry 2 54 52 53 subrot. 



Industry 9 57 42 47 kirtl. (subrot.) 



Coraopolis 8 53 42 48 kirtl. (subrot.) 



® Simpson, C. T. A descriptive Catalogue of the Naiades, or Pearly 

 Fresh-water Mussels. Detroit, 1914. All other references given without de- 

 til may be found in this work. 



i'^ The first column gives the locality; the second the number of specimens 

 at hand; the third, fourth and fifth, the maximum, minimum, and average of 

 the percentage of the diameter ; and in the last column, the name of the 

 variety represented is given. When several forms are present, the first name 

 is that of the prevailing (average) form, the other (in parenthesis) that of 

 the less abundant one. 



