LYMN.EIDJE OF NORTH AMERICA. 101 



"The species is named in honor of Mr. Scudder, who first indicated 

 the presence of Mollusca in these beds." (Ckll.) 



Galba sieverti (Cockrell). Plate XVII, figure 14. 



Lymncea sieverti Cockerell, Bull. Amer. Mus. Nat. Hist., XXII, p. 461, 

 fig. 3, 1906; Nautilus, XXII, p. 70, 1908. 



"Shell: "Long. 8 mm., lat. 4J4, with about five rounded whorls; 

 length of aperture about 5 mm. ; sutures impressed ; sculpture weak ; 

 aperture contracted." (Ckll.) 



Type : University of Colorado. 



Horizon : Florissant formation ; Oligocene Period. 



Locality: Station 1, vicinity of Florissant, Teller County, Colo- 

 rado. 



Remarks : "This has the pointed spire of L. meekii Evans and 

 Shumard, of the White River group, but it is much smaller and has 

 more rounded whorls. The elongate narrow aperture is more like 

 that of L. meekii than of L. shumardi Meek and Hayden. The much 

 more convex whorls distinguish it from L. similis Meek, and L. vetusta 

 Meek, from the Bridger Eocene. 



"The specimen shows the interior of the shell, and the outside of 

 a portion near the mouth. It is of course dextral, though from the 

 manner of its preservation the aperture shows on the left side." (Ckll.) 



Sieverti is a neat little species, having affinities, apparently, with 

 the truncatula group of Lymnseas. 



Galba florissantica (Cockerell). Plate XVII, figure 5. 



Lymncea florissantica Cockerell, Nautilus XXII, p. 69, November, 1908. 



"Shell : "Length, 21 mm. ; diameter, about 10y 2 ; spire short, 

 scarcely over 5 mm. long, the whorls moderately convex; body-whorl 

 not very convex, with coarse, shallow, vertical grooves." (Ckll.) 



Type: University of Colorado. 



Horizon : Florissant formation, Oligocene Period. 



Locality : Station 1, near Florissant, Teller County, Colorado. 



Remarks: Prof. Cockerell (op. cit.) believes that this species 

 is a Miocene representative of Galba emarginata. Emarginata is, how- 

 ever, quite different (see the figures and descriptions in the systematic 

 portion of this work) and, in fact, is a modern species, possibly differ- 

 entiated since the Glacial Period. The general shape of the fossil, so 

 far as that can be made out from the photograph of the rather im- 

 perfect specimen kindly provided by Prof. Cockerell, would seem to 

 place it in the palustris group of Lymnaeas. It is quite unlike the other 

 described species of the Oligocene Period. 



