MONTGOMERY: GORDIACEA. 39 
spondingly concave on the median side. Viewed from the side (Fig. 65) 
each shows a more or less conical outline, broadest at the proximal end, 
rounded at the distal end. The dorso-median margin is slightly thickened. 
The flattened planes of the two lobes are not parallel, their dorso-median 
margins being much closer together than the ventro-median; the proximal ends 
of their dorso-median margins are in contact, while the ventro-median margins 
are farthest apart proximately (Fig. 66). The median plane between the 
two lobes is vertical to the flattened plane of the posterior end of the body 
proper. The tail lobes may well be termed leaf-shaped, 
Cuticle (examined in alcohol only, since it seemed inadvisable to section the 
single specimen at hand). The surface (Fig. 64) viewed with low powers 
of the microscope, shows very plainly a system of deep intersecting lines, be- 
tween which lie slightly elevated areolæ of rhombic or rhomboid outline. 
There are necessarily two systems of parallel lines; and in one of these two 
systems the lines tend to occur in pairs. 
Color. The body is a uniform rufous-brown color, the tail lobes somewhat 
lighter. The mouth region of the head is yellowish, behind which follows a 
zone of a nearly black color; the posterior portion of the head is but little 
darker in color than the body. 
Dimensions. Length, 158 mm. ; greatest diameter of head, 1 mm.; greatest 
diameter of body, 1.5 mm. 
Comparison. This species may be very sharply distinguished from any 
other Gordiacean yet described, by the torsion of the neck through an angle of 
nearly half a circle, and by the extreme flattening of the tail lobes. It is the 
only species known from the Sandwich Islands. 
9. G. capitosulcatus, n. sp. 
Figs. 67-69, Plate 9; Fig. 70, Plate 10. 
(Type, 1 male: Harvard coll. 1466 a, Cuba.) 
Form. The body is dorso-ventrally slightly flattened, with slight dorsal 
and ventral median grooves. The head (Figs. 67, 69) is flattened laterally, 
higher than broad, and is separated from the body by a slight constriction 
(neck). The head has the greatest diameter at the anterior end, where it is 
obliquely truncated, the dorsal margin projecting slightly farther forwards 
than the ventral. The terminal aspect (Fig. 67) of the head is concave, the 
large mouth opening situated in the median line, nearer the ventral than the 
dorsal margin of the head. At each anterior dorso-lateral margin of the head 
is a ring-shaped prominence (Fig. 69), which surrounds a pit-like depression. 
It would be impossible to determine the structural significance of these pits 
without sectioning the head, but this was not permitted on the single speci- 
men examined, 
The tail lobes (Fig. 70) are slightly divergent; each is terminally rounded, 
nearly cylindrical on cross section, but concave on the median surface. The 
lobes are long and slender, and apparently bear no hairs or spicules. The 
