34 BULLETIN: [MUSEUM OF COMPARATIVE ZOOLOGY. 
Cuticle (Figs. 32, 33). Areolated; the areolæ variable in size and form, 
usually elongate-oval or irregularly pentagonal in outline. Their longitudinal 
axis is usually nearly perpendicular to that of the body, and they tend to pro- 
duce transverse rows or chains, in each of which rows some of the areol are 
confluent. Narrow, shallow grooves separate neighboring parallel rows of 
areolæ ; and beneath the areolæ a system of fine intersecting lines is seen. 
No interareolar bristles or hairs are present. 
Color. In the female (three specimens examined) the extreme tip of the 
head is white, this is followed by a light buff ring, and immediately behind 
the latter a broad transverse reddish brown ring. The cloacal aperture is 
immediately surrounded by a thin black ring, and around the latter is a much 
broader circular area of a reddish brown color. The rest of the body is a deep 
yellowish brown in one specimen; a light chocolate color in the other speci- 
men. Color of the male (a single specimen) similar to that of the female, 
but darker, a deep chocolate color; a nearly black ring surrounds the cloacal 
opening, while the postcloacal integumentary ridge is slightly lighter than the 
surrounding parts. 
Dimensions. Male, length, 290 mm. ; greatest diameter, 1.1 mm. Female, 
length of largest specimen, 395 mm., ; greatest diameter, 1.7 mm. 
Comparison. This species is quite similar to the European G. tatrensis 
Janda, but differs from it in that all the arcole are of a dark color and 
there are no groups of areoles forming white spots; and in the male the tail 
lobes are shorter and thicker, and there is no “knorriges, glattes, dreiwandiges 
Höfchen ” around the cloacal aperture, such as is described by Janda (93). 
It also differs from G. violaceus Baird in the manner of distribution of the | 
spicules on the tail lobes, and in the confluence of the areolæ. Itis however 
most closely allied to G. platycephalus, n. sp. ; these resemblances will be dis- 
cussed under the heading of that species. 
Especial Diagnostic Characters. The dense arrangement of the irregular 
areolæ, which have a tendency to produce transverse rows, and the tendency 
to confluence of the arcoles ; the comparatively robust form of the body; the 
short, thick tail lobes in the male, with the conical spines on their ventral sur- 
face, the obscure posteloacal integumentary ridge, and the ventral depression 
within which the cloacal aperture lies. 
Geographical Distribution. The type specimens (2 males, 1 female) are 
from Fort Bridger, Wyoming; and another female from South Montana (coll. | 
Acad. Nat. Sci. Philadelphia). 
5. G. platycephalus, n. sp. | 
Plate 6; Figs. 46-49, Plate 7. | 
(Type of female : coll. Acad. Nat. Sci. Phila., Guatemala. Type of male: 
coll. Acad. Nat. Sci. Phila., South Montana.) 
Form of Female. Anterior portion of the body attenuated and flattened in 
all.specimens, and the head constricted from the body. The head (Figs. 42, 6, 
