14 University of Michigan 
partially suppressed and in old shells both become jagged, and 
usually one well-developed, slightly curved, long lateral, with 
sometimes an indication of another more dorsad; beak cavi- 
ties rather shallow, showing or just obscuring the dorsal scars ; 
anterior muscle scars deep and sculptured by anastamosing 
lamellae; posterior scars well impressed only at the anterior 
end; nacre white to salmon or lavender, without distinct, cop- 
pery tinge; radially striate and iridescent in the younger shells, 
but thickened and minutely pebbled anteriad in the older 
specimens. 
VARIATION IN &. liebmanni cuatotolapamensis, n. subsp. 
So Rs 
an ace: 
SO eG » a 
cy ey oO a, 
ae) 5 
z v= 8.8 
pe ey a 
E. liebmanni 103-56 43 (Philippi, 1849) 
E. sphenorhynchus 71 52 33 (C. and F., 1894) 
Fig. 6 (smallest) 55 51(28) 33(18) (heavily ornamented ) 
Fig. 7 (left valve) 62 50(31) 34(21) (ornamented) 
Fig. 20 (right valve) 62 58(36) 37(23) (see below) 
Fig. 21 65 55(30) 34(22) (smooth and shiny ) 
Fig. 24 74 54(40) 33(24) (ornamented) 
Fig. 23 (left valve) 78.5 48(38) 29(23) (smooth; see below) 
Fig. 25 (very heavy) 79 53(42) 42(33) (strongly eroded) 
Fig. 22 (type sub- 
species) 81 53(43) 35(28) (ornamented) 
Meanof2ospecimens 69 54 34 
Extremes of lot 55-83 48-58 29-42 
This is a smaller form than typical liebmanni, with, appar- 
ently, a stronger tendency towards ornamentation. Simpson 
(1914) omits any mention of the ornamentation in his descrip- 
tion of E. liebmanni, but Philippi (1849) says: “The beaks 
of my examples are very widely and strongly eroded; how- 
