456 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 



Iii 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 Iudustries'of the United States, Section 

 I » Washington, 1834. 



The illustrations which accompany this paper are the work of my wife, 

 Margaret B. Linton. 



Order CESTOIDEA. 



Family DIBOTHRIIMS Diesing. 



Dibothrium Rudolphi. 



Tcenice spec, of Authors. 



Bhytelminthus, Bhytis, Alyselminthus, and Helsya Zeder. 



Bothriocephalus (Diboihrius) Rudolphi. 



Diphyllobothrium Cobbold. 



Dibothrium Diesing. 



Dibothrium manubriforme, sp. nov. 



[Plate I, Figs. 1-4.] 



Head enneate, 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 appearauceof the head when viewed 

 laterally is therefore somewhat like a, ball-bat, the constricted part rep- 

 resenting the handle. Two longitudinal fossa 1 (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 fossa?, give the head when viewed in front a four-lobed appear- 

 ance. The edges of the lobes bordering the lateral fossa? 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 posteriori}', appressed 

 slightly anteriorly, and raised into two small eminences on each side of 

 the secondary fossse. 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 



