MONTGOMERY : GORDIACEA. oo 
longitudinal rows which form ridges on the body surface. The areole vary 
considerably in form and size. 
Color. A pale transparent yellowish white, the female of a deeper buff 
color. In the female the cloacal opening is immediately surrounded by a 
narrow, reddish brown ring. 
Dimensions. Length of largest male, 278 mm. ; greatest diameter, .6 mm. 
Length of largest female, 283 mm. ; greatest diameter, .8 mm. The females 
are a little longer and broader than the males, but both sexes are very slender, 
Comparison. This species stands closest to (Y. violaceus Baird, but differs 
from it in the form of the tail lobes, and in the arrangement of the spicules on 
them, as well as by its very slender form. 
Particular Diagnostic Characters. Very slender and short, of a pale yellowish 
or buff color. Areola small, close together, with a tendency to form longitu- 
dinal ridges. A line of long hairs to each side of the cloacal aperture in the 
male, and spicules on the tail lobes. 
Geographical Distribution. New York, Maryland, and one specimen secured 
by me in a spring in Chester County, Pennsylvania. Leidy” type specimens 
were also found in a spring. 
4. G. densareolatus, n. sp. 
Figs. 32-33, Plate 4; Plate 5. 
(Types: Leidy coll. 5063, Fort Bridger, Wyoming.) 
Form of Female. Head end (Figs. 34, 35) conical, terminally rounded, 
the terminal portion slightly constricted off; mouth opening terminal. An- 
terior portion of the body narrower than the middle and posterior portions. 
With more or less pronounced dorsal and ventral median lines. Posterior end 
(Figs. 38, 39) slightly widened horizontally, obtusely truncated, with a shal- 
low vertical groove on its posterior aspect, in the middle of which the cloacal 
opening lies. 
Form of Male. Generally similar to but more slender than the female. 
The tail lobes (Figs. 36, 37) are short, thick, asymmetrical, and divergent. 
The cloacal aperture is small, circular, and immediately enveloped by a dark 
ring ; it is situated anterior to the tail lobes, on the ventral surface of the body. 
On the antero-ventral surface of the tail lóbes is an integumentary (not purely 
cuticular) ridge of slight elevation, the two arms of this ridge converging and 
joining just behind the cloacal aperture. The ventro-median surfaces of the 
tail lobes are concave. From the cloacal aperture, and embracing it, there 
extends cephalad, for a distance about equal to the length of the shorter tail 
lobe, a comparatively wide groove on the ventral surface of the body; at each 
antero-lateral edge of this groove lies a rounded prominence or ridge. The 
ventro-median surfaces of the tail lobes and the posteloacal integumentary 
ridge are covered with short conical cuticular spicules, which extend cephalad 
to each side of the cloacal aperture. 
