LYMNZIDZ OF NORTH. AMERICA. 459 
shouldered appearance to the whorls, rapidly increasing in size, the 
last whorl being inflated with numerous rather marked transverse 
coste, minutely wrinkled; suture somewhat deep, regularly impressed ; 
aperture elongately ovate, effuse, approaching patulous, pearly white 
within; outer lip simple, the margin connected by a slight calcareous 
deposit ; columella somewhat twisted, but straight in front.” (Call). 
Length. Breadth. Aperture length. Breadth. 
13.40 7.10 9.00 5.90 mill. (Call.) 
16.82 8.88 ie of He 
13.40 7.10 pire Gohoe average of 9 spec. (Call). 
SHELL: Varying from globose to elongate-ovate, rather solid; 
color (of dead shells) white ; surface dull, lines of growth heavy, wide, 
somewhat regular and in some cases equidistant; surface of body 
whorl with numerous heavy, rounded, irregularly placed ribs or coste ; 
the surface is minutely wrinkled but distinct spiral lines cannot be seen 
in the specimens examined; apex smali, smooth, roundly flattened, 
spermaceti—white in color; whorls 4-4%2, convex, rapidly enlarging, 
sometimes slightly shouldered; spire broadly or sharply conic, varying 
in length from one-third to one-half the length of the shell, flattened 
or pointed in different specimens; sutures deeply impressed ; aperture 
varying from round to elongate-ovate, in some specimens somewhat 
effuse; peristome thin, sometimes internally thickened; parietal wall 
with a heavy callus which is more or less erect, leaving a well-defined 
umbilical chink; axis thickened, only slightly twisted and with a faint 
plait. (Phil. Acad. specimens). 
Length. Breadth. Aperturelength. Breadth. 
14.50 10.00 9.50 4.50 mill. Type, Smithsonian. 
9.25 6.00 5.50 S10" =, a ss 
16.25 8.50 9.00 4250) Phil. Acad. (62603. ) 
14.00 8.00 8.25 Aa) as % = a 
10.50 6.50 6.00 oot o “4 
9.50 6.00 5.50 S150 aot fs s % 
Types: Smithsonian Institution, four specimens, No. 31276. 
Type Locatiry: Lake Utah, Lehi, Utah. 
ANIMAL, JAW, and GENITALIA: Not recorded. 
Rapu.a: Call says, “The dentition differs from typical R. ampla 
Mighels very materially,’ but he does not say in what manner. In 
another place (T. c. pp. 47, 48) he says, “dentition unpublished.” 
RAncE: Utah. The relation of this species to the fauna of the 
ancient Lake Bonneville is not clearly known. There is reason to be- 
lieve that it is a descendant of the Pliocene Lymnea Kingii. From 
the records it would seem that it is a new species evolved since the dep- 
