40 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
cloacal aperture is situated on the ventral surface of the body, a short distance 
in front of the point of union of the two lobes. 
Cuticle (Fig. 68). With small elevated areoles, situated close together. 
The areoles are somewhat variable in size and form, but are mostly rounded- 
polygonal in outline. Their surface is not smooth, as in the other species of 
the genus examined by me, but with irregular short tubercles. Interareolar 
bristles are apparently absent. 
Color. Pitch-black to the naked eye, but with a brownish tinge when 
viewed with the microscope. The margins of the ring-shaped prominences of 
the head are of a whitish color. 
Dimensions. Length, 165 mm.; greatest diameter, 9 mm. 
Especial Diagnostic Characters, The presence of depressions on the anterior 
dorso-lateral margins of the head ; the roughened surface of the areoles; the 
intense black color. 
Comparison. This form differs from G. violaceus, densarcolatus, and platy- 
cephalus by the roughened surface of the areoles, the coloration, and the 
presence of the pits on the head. It has no close resemblance to any of the 
species described by Camerano from South America, and on the whole appears 
to be a well defined species. 
10. G. paranensis Camer. 
Wigs. 71-74, Plate 10. 
G. paranensis Camerano, ’92, 04. 
G. paranensis Camer., Römer, *96. 
(1 female, 5 males: Harvard coll. no. 1478, Casabianca, Chile.) 
Form of Female. Body somewhat flattened dorso-ventrally, without well 
marked median grooves, Head cbnical, concave on the terminal aspect, 
mouth terminal ; head not constricted from the body. Posterior end (Fig. 71) 
truncated, with a circular depression on its terminal aspect, in which the 
cloacal opening lies ; this posterior end of the body is round on cross section, 
while the immediately preceding portion of the body is much flattened dorso- 
ventrally. 
Form of Male. Body more slender than in the female, and with more or 
less well marked median grooves. In one male (Fig. 74) the head end is 
conical with rounded tip; in the others it is separated from the body by a 
slight constriction, and is terminally truncated, the terminal face concave 
(Fig. 73) ; on this terminal aspect of the head in one specimen is a vertical, 
median ridge, to each side of which is a depression. A conical and a truncate 
form of head being found in different specimens of this species would lead to 
the conclusion that the truncate form, in which the anterior aspect of the head 
is concave, is probably due to a muscular contraction of the tip of the head. 
The tail lobes (Fig. 72, a, b) are comparatively short and thick, flattened on 
their proximo-median surfaces as well as on their dorso-lateral surfaces, 
