6 land and fresh-water shells of n. a. [part iil 



Spurious and Extra-limit al Species of Ampullariid^e. 



This family does not appear to belong to the molluscous fauna 

 of the United States, but rather to that of South America. I have 

 not, therefore, included the Mexican species. 



AmpuUuria crassa, Deshayes. Vide Melantho ponderosn. 



Amptdlaria horeali.i, Valenciennes, in Humboldt and Bonpland, Rec. d'Obs. 

 II, 2(i0, is probably Lunatiu htros, Say. Ferussac (Bull. Zool. 1835, 

 2d sect. p. 33), in reviewing Valenciennes' work, refers it to a large 

 marine Nntica figured by Chemnitz. The description is as follows : — 



"Shell ventricose, globose, heavy, thick, smoky white, broadly 

 umbilicated, with longitudinal strire but no wrinkles. 



St. Pierre and Miquelon, near Newfoundland. 



This species resembles Am. (/uyanensis. Its proportions are the 

 same ; it is longitudinally striate, but its shell is at least three times 

 as thick, so that it is quite heavy. It is also distinguished by its 

 very large umbilicus, while A. guyanensis has none. The color is 

 yellowish or light reddish on the top of the last whirl ; the base is 

 white." — Valenciennes. 



AmpuUaria rotundata, Say. — Shell remarkably globose ; length and breadth 

 equal, dark brown, but becoming olivaceous towards the aperture ; 

 spire but little elevated ; suture moderately impressed ; body whirl 

 a little undulated instead of being wrinkled ; these undulations be- 

 ing 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 stratified ; nucleus on 

 the side towards the labium submarginal. Length less than one 

 inch and four-fifths ; greatest breadth about the same. 



For this interesting species we are indebted to Captain 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. globosa, 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 perceptible, 

 distant, brownish bands, particularly towards the base. It may, 

 however, be only a variety of that species. (Say.) 



AmpuUuria rotundata, Say, N. Harmony Diss. II, 245 ; Discr. 

 27 ; Binney's ed. p. 147, pi. Ixxv. — Philippi, in Chemn. 

 ed. 2, p. 68. 



