147 



Ampluria rotundata. — Shell remarkably globose; length 

 and breadth equal, dark brown, but becoming olivaceous towards 

 the aperture : spire but little elevated : suture moderately impress- 

 ed : body whirl a little undulated instead of being wrinkled ; these 

 undulations being very perceptible to the finger within the shell ; 

 aperture within on the margin thickened equally all round, and 

 fulvous, with a slight groove for the reception of the operculum, 

 hardly visible but palpable : within somewhat perlaceous ; a little 

 darker on the columella : umbilicus small, narrow : operculum 

 calcareous, deeply and concentrically rugose, so as to appear strati- 

 fied ; nucleus on the side towards the labium sub-marginal. 



Length, less, than one inch and four-fifths; greatest breadth, 

 about the same. 



For this interesting species, we are indebted to Capt. Leconte, 

 of the Topographical Engineers, who informed me that he found it 

 in St. John's river, in Florida. 



It is most closely allied to the A. glohosa, Swainson, a native of 

 the rivers of India. But that shell is rather less globose, and does 

 not appear to have the almost regular, but slightly elevated and 

 very numerous undulations so perceptible towards the aperture on 

 the body whirl of this species ; which has also a few hardly per- 

 ceptible, distant, brownish bands, particularly towards the base. 

 It may, however, be only a variety of that species. 



Ampullaria depressa. — As the name depressa, of the Ap- 

 pendix to Long's Expd. p. 264, is preoccupied by Lamarck for a 

 fossil species, it may be changed to paludosa. 



Ampullaria elagellata. — Shell subglobose, olivaceous 

 brown, with 15 or 16 revolving, dull reddishbrown, slender bands : 

 spire conic, moderately elevated, acute: body whirl regularly 

 rounded, more obviously undulated or obtusely wrinkled near the 

 aperture : umbilicus free, obvious : labrum a little dilated : within, 

 reddish brown : labium, columella, and the margin of the labrum 

 white : operculum horny. 



Length, over one inch and a half; greatest width, one inch and 

 two-fifths. Inhabits Mexico. 



Occurs in plenty a short distance below Vera Cruz. We found 

 them immediately behind the sand-hillocks of the coast, in situa- 

 tions which, in rainy seasons, are covered witli fresh water. We 

 did not see a living specimen ; they were mostly decorticated and 



