MELxVNTHO. 



43 



are destitute of an elevated line, the suture is not so deeply impressed, 

 and the aperture is narrower above. 



Animal with the foot larger, suddenly a little dilated each side before 

 and truncate in front, widely; foot livid, thickly maculated with irregular 

 orange spots, which are much smaller beneath ; head and tentacula spotted 

 with orange ; eyes on a prominent angle, at the external base of the ten- 

 tacula. 



I found the animal viviparous in October ; the young shell had then 

 three complete whirls, which were spirally striated. (^Suy.) 



In the above description no locality is given, but there can be no 

 doubt that the shell described is the form common in the Delaware 

 River. I have, therefore, taken this form to be the type of the 

 species. From one of these my description ayd figures T9 and 81 ' 

 arg drawn. Younger specimens are pi'oportionally more globose 

 than the one figured, and the spire is often not truncated, but 

 consisting of 5 whirls, the apex being perfect. Fig. 80 is drawn 

 from a specimen found in the Susquehanna, more elongated in 

 shape, and truncated at the apex alone. In New England and 

 Canada the shell is less elongated, with more pyramidal spire. 



Say figured another shell as Faludina decisa 

 in the American Conchology, and gave two 

 figures of it, from one of which mj figure 84 is 

 copied. At this time he repeated the descrip- 

 tion from the Encyclopedia, and added the fol- 

 lowing remarks and references. 



This species is common in various parts of the 

 Union; Dillwyn informs us that Miiller and others 

 have incorrectly quoted Lister's figure for their Helix 

 angularis. Petiver, Gaz., pi. 106, figflS. (iSay.) 



The figure copied above does not agree wi,th 

 that given in Nicholson's Encyclopedia. I 

 should rather refer it to lle- 

 lantho ponderosa (page 37). 



To the typical form of M. 

 decisa the following synonyms 

 may without diDubt be referred. 

 Figure SS* is a fac-simile of 

 Helix dissimilis, Wood, of 

 which no description nor local- 

 ity is given. It is evidently intended for 

 this species, though the true name decisa is cochiea, &c., 



Fig. 84. 



Fig. 85. 



Paludina decisa. 



Fig. 86. 



