MELANTIIO. 



49 



Fig. 99. 



Fig. 100. 



Yuuug of M. Integra. 



Fig. 101. 



more heavily tliickened and white above and below. Length of axis 24, 

 greatest breadth of body whirl 15 ; length of aperture 15, breadth 11 mill. 

 Operculum as in J/, decisa. 



In general terms it may be said that the form known as M. 

 Integra differs from 31. decisa by being more elongated, having 

 a perfect apex, a smaller aperture, more 

 prominent revolving strias, and a whiter 

 aperture. These characters are only com- 

 parative. The two forms are not distin- 

 guished by any decided, constant, specific 

 characters. Fig. 99 represents young 

 shells, which are more globose, compara- 

 tively, than the more mature ones. 



Two curiously deformed 



specimens of 31. integra in 



the collection are figured in 



Figs. 100 and 101. 



Reeve places Paludina 



ponderosa in the synonymy 



of Pal. decisa. On page 37 



will be found an enumeration 



of the constant specific char- 

 acters of 3IeIantho po7iderosa. 

 Paludina microstoma, Kirtland, is added 

 to the synonymy on authority of Mr. An- 

 thony, who tells me Prof. Kirtland described 

 it before meeting with the description of integra. On seeing Mr. 

 Anthony's cabinet he was at once convinced of their identity. 



Paludina microstoma, 1. c. — An uudescribed species Fig. 102. 



of Paludina, found frequently associated with the P. 

 decisa, and distinguished by its elongated spire and 

 small mouth. (Kirtland.) 



Paludina rufa, Halderaan, is said by him (1. 

 c.) to be distinguished by a reddish color and 

 entire apex, but may be a variety of Pal. decisa. 

 The reddish or pinkish tint within the aperture 

 (sometimes divided into bands) appears to dis- 

 tinguish this form of the species, which occurs 

 in the Southern as well as Northern States. Puof. Haldeman's 

 original specimen of Pal. rufa, together with all those from which 



M. integra, deformed. 



Pahidina rufa. 



