.^^ University of Michigan 



Simpson have followed him. However, catillus Con. differs 

 from coccineiis Con. (figured on the same plate) by the greater 

 ■obesity of the shell, and this is exactly the character by which 

 U. solidus Lea differs from coccineus. Thus, cdtillus clearly 

 is the same as solidus, having priority over it. 



Utterback was the first to recognize this, but his treatment 

 of this group (introducing, besides PL (obi.) catillus, another 

 species called PL catillus Con. =^ solidus Lea) is contrary to 

 all nomenclatorial rules. According to Ortmann, all these 

 forms are variations or varieties of PL cordatum (Raf.). 



Pi^EUROBEMA cocciNEUM paupErcuIvUM (Simpson), 1900 



Type locality: Niagara Falls. 



Quadrula coccinea paupercula Simpson, 'coc, p. 789 (not Unio pau- 

 perculus (Lea) '61) = Quadrula paupercula (Lea), Simpson, '14, p. 862. 

 Quadrula coccinea magnalacustris Simpson, '14, p. 884. 



Simpson's Quadrula coccinea paupercula is not a homonym 

 of Unio pauper cuius Lea, the original form of the name of 

 Lea's species. It is a forbidden name as long as the two 

 forms are placed in the same genus. If they are placed in 

 different genera, as Quadrula paupercula (Lea) and Pleuro- 

 bema coccifiemn pauperculum (Simpson), the name pauper- 

 culus is valid in each case. 



i . Plkurobe^ma pyramidatum (Lea), 1831 



Type locality: Ohio. 



Obliquaria rubra Rafinesque, '20, p. 314 (standing under genus 

 Amblema. 



Pleurobema mytiloides Rafinesque, '20, p. 313, pi. 82, f. 8, 9, 10. 



Unio pyramidatus Lea, '31 (not '34 as given by Simpson), p. 109, 

 pi. 16, f. 39. 



U. triangularis Raf. = U. lateralis Raf. = U. sintoxia Raf. = U. 

 mytiloides Raf. := U. rubra Raf. = U. pyramidatus Lea, Conrad, '34, 

 p. 72. 



U. mytiloides Raf. = f/. rubra Raf. = t/. pyramidatus Lea, Ferus- 

 sac, '35, p. 28; Conrad, '36, p. 41, pi. 20. 



