344 GEOLOGICAL SURVEY OF THE TERRITORIES. 
with the digitate processes as in the European form. Its oceurrence, 
however, in this country and its being an intermediate form between B. 
vernalis and B. grube: shows that the genus Hubranchipus is not suffi- 
ciently distinet to be regarded as a valid genus. As our description is 
brief and gives only the salient points observed in alcoholic specimens, 
we reproduce Mr. Forbes’s original descriptions, drawn up from living 
examples: 
“An important character, constant in the large number of both sexes 
which I have examined, is found in the abdominal segments, which are 
narrowed in front, with rounded anterior angles, while the posterior 
angles are produced backward, giving a decidedly serrate appearance 
to the abdominal margin. The last two abdominal segments are closely 
united and broader than the preceding. 
“The antenne extend a little beyond the eyes, and terminate in a 
cluster of about five slender olfactory clubs. The frontal appendages of 
the male are considerably longer than the claspers, to the front inner 
base of which they are attached, the line of attachment being parallel 
to the length of the basal joint. Their form is irregularly oval, the 
inner edge being regularly convex on its distal three-fourths, and the 
outer sinuate-convex on basal two-thirds, and slightly concave on ter- 
minal third. Both margins are pectinate, except near base, with thick 
blunt teeth, which are ‘longest on, the basal half of the outer margin, 
where they are as long as the undivided part of the appendage is wide. 
At the middle of this : margin the teeth become suddenly shorter. On 
the inner margin they are longest near the middle, regularly lessening 
towards each end. The under (posterior) surface of the appendage, as 
well as the teeth, is set with short spines, each springing from an in- 
flated base. The claspers of the male are shorter and stouter than in 
LE. vernalis. The basal joint is soft and inflated and bears a corneous 
rounded tubercle at its inner base (wanting in vernalis). The second 
joint is stout and regularly incurved, strongly angulated at its base in 
front where it is received into the first joint. A long strong tooth, 
about half as long as the joint, extends backward and a little inward 
from near its base. The rounded tip of this tooth is thickly set with 
minute, low, circular elevations, each with a central depression, within 
which is a disk-like elevation, the whole having the appearance of a 
minute sucking disk. The tip of the clasper is expanded and flattened 
within so that the inner (anterior) part has a spatulate form, while the 
opposite surface rises into a thick prominent ridge, giving to a trans- 
verse section of the tip the form of the letter T. The anal appendages 
are linear-lanceolate, as long as the last four segments of the abdomen, 
and plumosely haired to the base. The ovisac of the female is as broad 
as long, three lobed behind, with the middle lobe the largest. 
“Length of a full grown male, including anal stylets, 20""; width, 
6™™; across eyes, 4°"; clasper, 4.5""; frontal appendage, 5™™ by 3™”. 
The largest females were a little more slender than the males.” 
Genus STREPTOCEPHALUS Baird. 
Plate XII; figs. 1-7. 
Streptocephalus Baird, Annals and Mag. Nat. Hist. 2d Ser. XIV, 219. 1854. 
Heterobranchipus Verrill, Amer. Journ. Se. xlviii, p. 250. 186 9. 
_ Streptocephalus Verrill, Proc. Amer. Assoc. Adv. Se. July, 1870. 
Body rather slender, much more so than in Branchipus. 2d anten- 
ne of male 3-jointed, remarkably long and large, tortuous and twisted, 
