YIVIPARA. 25 



molluscous fauna of Europe and America are entirely distinct, 

 we are justified in considering that this Vivipara is not identical 

 with the V. contecla. 



There exist in Europe two species of Vivipara: the conteda 

 (Cyclostoma), Millet, and vivipara {Helix), Lin. It is to the 

 former that our species bears so strong a resemblance, and not to 

 the vivipara, as suggested by authors. I have copied Reeves' 

 figures of both species (Figs. 45 and 46) that those not having 

 access to foreign works may compare them with our shells. V. 

 contecta is described as being composed of 5^ prominently turned 

 whirls, convoluted so loosely as to leave a deep umbilicus in the 

 centre ; while V. vivipara has one whirl less, has moderately 

 ventricose whirls, and is more constrictedly convoluted — the um- 

 bilicus being reduced to a mere chink. 



I have elsewhere remarked that F. contedoides seems, in re- 

 spect to form, to hold the same relation to V. georgiana as V. 

 conteda does to V. vivijDara. 



I have been unable to obtain living specimens of this species, 

 or any preserved in spirits, from which to examine the lingual 

 membrane. 



Mr. Say first mentions this species as early as 1817, describing 

 it as identical with the European V. vivipara, as a Limn^a, and 

 later as a Paludina. I give below a copy of his description and 

 figures from the American edition of Nicholson's Encyclopedia 

 (Fig. 47), and the American Conchology (Fig. 48). It will be 

 observed that Say mentions three revolving bands instead of four. 

 I am inclined to attribute this to his overlooking the lowest band, 

 which is quite at the base of the shell and does not extend so far 

 towards the edge of the aperture on the inside. 



Paludina vivipara. Say. — Shell subconic, with six rounded whirls* 

 suture impressed, color olivaceous or pale, with three red-brown bands 

 of which the middle one is generally smallest, whirls of the spire with 

 but two ; aperture suborbicular, more than half the 

 length of the shell. pj„_ ^^^ 



It is doubtful whether or not this is the same as the 

 vivipara, but it certainly approaches very near to it ; 

 we, however, refer it to that species until a specific 

 difference can be indicated, which at present we are 

 unable to do ; the spire of this species is rather more 

 obtuse, and the suture not so deeply impressed, as 

 in the figures of the European specimens above 

 mentioned, j^ Paludina vivipara. 



