456 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 
In giving the specific names of fishes mentioned in this paper, I have 
used the nomenclature adopted by Prof. George Brown Goode in 
“The Fisheries and Fishery Industries of the United States, Section 
I.” Washington, 1854. 
The illustrations which accompany this paper are the work of my wife, 
Margaret B. Linton. 
. ORDER CESTOIDEA. 
Family DIBOTHRITDZ Diesing. 
DIBOTHRIUM Rudolphi. 
Taenie spec. of Authors. 
Rhytelminthus, Rhytis, Alyselminthus, and Helsys Zeder. 
Bothriocephalus (Dibothrius) Rudolphi. 
Diphyllobothrium Cobbold. 
Dibothrium Diesing. 
Dibothrium manubriforme, sp. nov. 
[Plate I, Figs. 1-4. ] 
Head cuneate, tetrangular, truncate in front, tapering posteriorly, 
constricted into a cylindrical neck-like part near posterior, then expand- 
ing so that the posterior end of the head resembles one of the anterior 
segments of the body. The general appearance-of the head when viewed 
laterally is therefore somewhat like a ball-bat, the constricted part rep- 
resenting the handle. Two longitudinal fosse (bothria), laterally placed, 
extend from the anterior part of the head to the constricted part. Each 
of the marginal lobes thus formed is indented at the anterior extremity 
by a short but deep secondary fossa, which, together with the two lat- 
eral fossx, give the head when viewed in front a four-lobed appear- 
ance. The edges of the lobes bordering the lateral fossx are thin-lipped 
and flexible; anteriorly there is a transverse elevation forming both a 
lateral and a marginal rim and making an obtuse angle between the 
front and the side of the head. The marginal lobes, when at rest, have 
a rounded outline, fullest in the middle, tapering posteriorly, appressed 
slightly anteriorly, and raised into two small eminences on each side of 
the secondary fossw. The head in a marginal view is somewhat flask- 
shaped. Seen from the front the head is squarish, with the angles 
rounded and the sides deeply cleft, the clefts rounded, the lateral clefts 
deeper than the marginal. Immediately back of the head the segments 
are very narrow, and for a greater or less distance, depending on the 
state of contraction, maintain about the same width as the base of the 
head. In some individuals the small anterior segments continue much 
farther back from the head than in the one figured (Plate I, Fig. 1). 
The segments are alternately short and long. This characteristic is 
quite plainly marked in those segments which immediately follow the 
