LYMNEIDZ OF NORTH AMERICA. 141 
has a somewhat pinched-in appearance, and the body whorl is distinctly 
shouldered; nuclear whorls 114, the texture resembling satin finish ; 
in outline the first part of the whorl is a small rounded knob about 
one-fourth the size of the second part, which is wider than high; in 
color it is shining yellowish-brown. (Pl. XLIX, figs. A, B.) 
Aperture 
Length. Breadth. length. Breadth. 
42.00 17.00 21.50 10.25 mill. Say’s Type. 
40.50 16.00 21.00 9.50 = 
50.00 25.00 27.00 1550. 9° ~Wake* Ontario: 
49.00 14.50 27.50 14.00 “ a - 
47.00 25.00 27.00 TOO) © Niagara River, IN. Y: 
41.00 19.00 22.00 13.00 “ Bear Lake, Mich. 
46.00 20.00 19.00 11.00 7 Romeo, Ill. 
46.00 20.00 22.00 11.004” Pigeon, Lake Ont 
57.50 24.50 29.00 13.00 - Lake Calumet, III. 
49.00 20.50 24.50 11.00 Erie Canal. 
43.50 19.75 21.00 10.50 “ Bitter Root River, Mont. 
46.50 22.50 24.50 12500 St leavinences Ravers 
Type: <Appressa; Academy of Natural Sciences of Philadelphia, 
two specimens. Jugularis, types not in existance. 
Tyre Locatity: <Appressa, Lake Superior; jugularis, original 
locality not stated by Say. 
AnimaL: Light or dark horn colored, tinged with bluish on the 
foot; tentacles triangular, flat, rather long and tapering; foot short 
and wide, truncated before and roundly pointed behind, 20 mill. long 
and 9 mill. wide in an individual of ordinary size. 
Jaws (Pl. VI, fig. A): The superior jaw arched, very wide and 
low, its cutting edge with a narrow, somewhat acute swelling in the 
middle, with a larger, convex swelling on each side; lateral jaws some- 
what triangular, the lower point of the triangle produced, long and 
tongue-like, directed downward and outward when the jaws are pressed 
out flat. The cutting edge of the jaws is very dark chestnut colored, 
almost black in some specimens. The form of the superior jaw differs 
considerably from the figures given in some European works, where 
the lower median portion is shown as concave with a slight median 
swelling. This may be due to the figure having been drawn from a 
different position. Cooke (Moll., p. 211) figures the jaws as they 
appear in the American specimens examined. 
Raputa: Formula (Pl. VI, fig. A) 
Fo t gt ye 4+it ye +st ey 
(46-1-46). Central tooth with a single spade-shaped cusp; first to 
nineteenth lateral teeth bicuspid; the mesocone very large, rather 
os 
