AMPULLARIA. 51 



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. 



Ampullaria rotundata, Sat — 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 gi'oove 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. iSay.) 



Ampullaria rotundata, Sat, N. Harmony Diss. II, 245 ; Discr. 

 22 ; Binnet's ed. p. 147, pi. Ixxv. — Philippi, in Chemn. 

 ed. 2, p. 68. 

 Ampullaria globosa, Haldeman, Mon. p. 8. — Swainson, Zool. 

 111. II, 119. 



I do not consider this and Vivipara elongata well established 

 American species. If actually found in Florida, they were probably 

 brought from Calcutta, where they both are found. 



Ampullaria urceus, Muller (^A. rugosa. Lam.), is found in Mexico. (Vid. 

 Humboldt & Bonpland, Rec. d'Obs. II, p. 258.) Of its presence in 

 the Mississippi Mr. Say says : The " Ampullaria urceus, L. (^rugosa, 

 Lam.) is stated in the books to inhabit the Mississippi River; but 

 I have never been so fortunate as to find it, or to gain any informa- 

 tion relative to it there. Mr. 0. Evans did me the favor to make 

 inquiry at various places on that river, and to exhibit, as somewhat 

 similar, a colored plate of the A. globosa, Swains., to persons from 

 whom information might be expected, and amongst others to some 

 Indians, who in general are known to be accurate observers; but no 

 one has seen any similar shell in the waters of the Mississippi. I 



