48 
Aucella kwoiekensis sp. nov. 
Plate X, figures 6, 7 
Resembles members of the inflata group, but differs markedly from all 
in proportions and in the fine, closely spaced, concentric striae. Byssal 
sinus unusually long. 
Although Pavlow suggests a very different history, yet it is quite 
possible that this form is ancestral to the crassicollis group. 
Dimensions. Holotype, a right valve — long axis, 42 mm.; short axis, 
38; semidiameter, 15; apical angle, 90 degrees. 
Locality. Zone of Quoiecchia aliciae, 235 yards from shore, on the 
left bank of a little brook which enters Harrison lake from the west, 1,450 
yards north of the mouth of Deer creek. 
Name. Kwoiek, Indian geographical name. 
Aucella crassicollis Keyserling 1846 
1846. Keyserling: Wissenschaftliche. Beobachtungen auf einer Reise 
in dar Petschoraland. 
The left valve is very strongly convex, and the left umbo is strongly 
incurved. Right valve, less so. The long axis of the left valve is about 
twice the short axis. The form is rather irregular. The external surface 
is marked by fine growth lines and concentric varices. The latter appear 
with maturity, but at slightly different stages in different specimens. 
Locality. Zone of Homolsomites poecilochotomus, Lonetree island; 
also on the southeastern shore of the peninsula, etc. 
Aucella solida Lahusen 
Aucella crassicollis var. solida Lahusen 1888: Mem. du Comite g^ol., 
St. Petersburg, vol. VIII, No. 1. 
This species somewhat resembles the last, but differs in that the long 
axis is not much greater than the short. 
Locality. Occurs associated with the last at all localities. 
Aucella harrisonensis sp. nov. 
Plate XI, figures 1, 2, 3 
Left valve, somewhat convex. Left umbo, slightly incurved. Right 
valve, flattish. Right umbo, short, obtuse, and almost ecurved. Shell, 
very thin, and, consequently, there is no ornament except joint growth 
lines. Concentric varices appear beyond 25 mm. from the umbo in some 
specimens. 
Dimensions. Holotype, a right valve — long axis, 32 mm.; short 
axis, 30; semidiameter, 8; apical angle, 95 degrees. Paratype, a left valve — 
long axis, 30 mm.; short axis, 20; semidiameter, 9; apical angle, 73 degrees. 
Locality. Zone of Homolsomites poecilochotomus, southeast shore of 
the peninsula, 200 yards from the south end. 
