136 AMERICAN JOURNAL 



siderable spaces, instead of being crowded together as in obesa 

 and fecunda. 



The small average number of young, together with the small 

 number of specimens sent for examination, induces me to regard 

 this species (or variety ?) as an imperfect breeder. In this it 

 falls very much below the most recently observed average of the 

 Erie C&nalintegra, — viz., 21 young to each adult. The number 

 of reversed young was three, being about 5 per cent., which is an 

 excess over the percentage of reversed young in Integra of the 

 Erie Canal, as recently ascertained from 88 specimens. Proba- 

 bly this large rate might be diminished by an examination of the 

 young of a larger number of specimens. I remember to have 

 experienced, several years ago, some of the same difficulties in 

 removing the soft parts from shells of the Ohio Canal that are 

 mentioned above, and the difficulties referred to the same species. 

 Whether the disparity in the average number of young and per- 

 centage of reversed young, together with the strong adhesion of 

 the soft parts to the shell, have specific value, I do not feel com- 

 petent yet to form an opinion. I present the matter for considera- 

 tion, hoping to interest other observers in similar investigations, 

 believing that the results will eventually tend to simplify our 

 acquaintance with the at present perplexing genus Melantho. 



