16 THE NAUTILUS. 



and at the same time looking for pearls. They have some common 

 names for certain kinds of mussels; and an official of button fac- 

 tories I met at Marietta, was kind enough to verify the names and 

 to give some additional information. 



" Mucket." Lampsilis ligamentina, also orbiculata. 



"Pig-toe." Quadrula obliqua, and the whole group of approxi- 

 mately the same shape, also subrotunda, aesopus, etc. 



" Warty pig-toe." Q. cooperiana, pustulosa, etc. 



"Nigger-head." Q.ebena; sometimes also Obovaria retusa. 



" Monkey face." Q. metanevra. 



" Butterfly." Plagiola securis. 



" Pocketbook." L, ventricosa, also capax. 



" Sand clam," or " Black sand clam." L. recta, occasionally also 

 Unio gibbosus. 



"Lady's finger." L. anodontoides, no doubt also fallaciosa. 



" Three-ridge washboard," or " Three-ridge," or " Washboard." 

 Q. undulata, also plicata, and multiplicata. 



" Razor-back," " Rudder-back," Hatchet-back." Proptera 

 alata (and, no doubt, Symphyn. complanata). 



Some other large and common mussels may have common names, 

 but I failed to find them out, e. g. U. crassidens, Tritogonia, Q. 

 lachrymosa. 



ON THE VALIDITY OF UNIO UNDATUS BARNES. 



BY BRYANT WALKER. 



(Concluded from p. 10. 



III. 



Is U. undatus Bar. = U. trigonus Lea. 



Lea's description of his trigonus is as follows : 



" Shell subtriangular, inflated, nearly equilateral, depressed before 

 the umbonial slope, angular behind; umbonial slope carinate; basal 

 margin emarginate ; substance of the shell thick, beaks prominent, 



