MONOGRAPH 



OF THE 



SPECIES OF THE GENUS PUPA 

 FOUND IN THE UNITED STATES. 



BY AUGUSTUS A. GOULD, M. D. 



[Extracted from the Boston Journal of Natural History, Vol. III. 395, and Vol. 

 IV. 350. Boston, 1843.] 



Having recently become interested in the examination of 

 the American species of the genus PUPA, I have found very 

 great confusion and uncertainty prevailing in regard to them. 

 The objects themselves are minute and difficult to examine ; 

 the number of teeth, which is one of the most important 

 specific characters, varies at different stages of maturity ; and, 

 what is still more unfortunate, Mr. Say, who gave names to 

 all the species which have been hitherto described, gave us no 

 figures in illustration of his descriptions. These are the 

 sources of confusion, and hence I have received, from our 

 best conchologists, a single species under four of the six names 

 that Mr. Say applied to his different species. 



It would be well, if, in writing descriptions, the teeth were 

 arranged as primary and secondary, indicating by the primary 

 those teeth which are always present when there are any, and 

 by secondary those which are superadded in the progress of 

 growth, or at maturity. Such a division would be applicable 

 in regard to almost every species. 



I have collected every specimen of PUPA which I could find 

 in the cabinets of Boston, and have received numbers from 

 Pennsylvania, Maryland, and Ohio, and I have carefully ex- 

 amined every individual. By means of a stationary micro- 

 scope of moderate power, and by employing a convex lens in 

 such a way as to bring the rays of the sun to a focus within 

 the aperture of the shell, I have been enabled to obtain a fair 

 view of the deeply seated teeth, 

 i 



