102 THE NAUTILUS. 
anterior slope is nearly straight; the posterior slope slightly 
concave; the left lateral slope nearly straight or only slightly 
convex and the right lateral slope concave; the apex is obtuse, 
smooth except for concentric wrinkles, situated nearly on the 
nedian line, slightly turned toward the right and at about one- 
third of the length; the lines of growth are tine, but distinct 
and regular, the surface is somewhat obsoletely wrinkled to- 
wards the margins, but there are no indications of radial striz; 
the color is a yellowish horn-color, slightly tinged with green. 
Compared with F. diaphana (Hald.) and F. kirklandi (Walk. ) 
to which it is most nearly related, it is less circular in outline, 
the apex is more prominent, the lateral and posterior slopes are 
unlike and the color is different from the former, and it is less 
elongated and has the apex more obtuse and less excentric than 
the latter. 
So far as appears from the small series examined, it would 
seem to he clearly entitled to specific distinction. 
TEL 
FERRISSIA (LAVAPEX) DALLI, nN. gp. 
2 Ancylus obscurus Clessin, Con. Cab., Ancylus, 1882, p. 19, 
pl. VI, fig. 4. 
Ancycus obscurus 2 Walker, Navut., XIII, 1903, p. 26, pl. I, 
figs. 16-18. 
Type locality, Lake Helena, Volusia Co., Fla. 
Type No. 25521 Coll. Walker. Cotypes in the collection of 
A. A. Hinkley. 
Tne doubt expressed in my paper of 1903 (1. c.) as to the 
identity of the Floridan species referred to obscurus Hald. by 
Dall proves to have been well taken. As shown by a compari- 
son of the description and figures given in 1903 as cited above 
and those of the genuine obscurus herein, the Floridan species 
is entirely different and is more closely related to F. peninsulz 
(P. and J.) than it is to obscurus. 
I have already (1. c.) called attention to the resemblance of 
the shell described and figured by Clessin as A. obscurus to this 
form. He gives no information as to the history of the speci- 
eS 
