147] PROTEOCEPHALIDAE—LA RUE 147 



examined and identified as belonging to this species as follows: in un- 

 numbered bottle, collection of La Rue, labelled "Black Bass, Large 

 mouth, Pyloric Region, Pelican Lake Minn., 1909," collected by E. G. 

 Davis; in bottle No. 10.151 labelled "Ex dogfish, Sandusky 0. Jy. 7, 

 1905"; in bottle No. 2d labelled "7/10/01. P. in B. Host. Amia calva- 

 Intestine" ; in bottle No. 85 "7/12/01. P. in B. Amia calva. Intestine" ; in 

 bottle No. 295, "8/4/01. P. in B. Amia, Stomach." The abbreviation 

 'P. in B.' stands for Put-in-Bay, Ohio, the locality of collection. The 

 bottles numbering 10.152, 2d, 85, 295 are in Professor Ward's collection. 

 These together with the material collected by Hankinson were turned 

 over to the writer for study through the kindness of Professor Ward. 



This is one of the largest of the species of Proteocephalus and it 

 is the largest species of that genus known at present from the fishes of 

 North America. It may attain a length of 41 cm. and maximum breadth 

 of 2.0-2.5 mm. The body is thick, fleshy and heavily muscled. In pre- 

 served specimens the outlines of the worm are somewhat rough, due to 

 the furrows on the margins of the strobila. The surface of the worm is 

 also rough. Longitudinal and transverse furrows are frequent. Espe- 

 cially noticeable is a deep median ventral furrow. On account of these 

 furrows the strobilation is more or less indistinct. Likewise the poste- 

 rior limit of the neck is frequently obscured by numerous transverse 

 folds which give an appearance of segmentation. 



The head is large and prominent. Its breadth is 0.75-0.875 mm. 

 according to Leidy, 0.82-0.88 according to Benedict. The heads exam- 

 ined by me measured 0.57-0.60 mm. Benedict describes the shape of the 

 head thus: 



"From the anterior face it presents a nearly square outline, with a deep 

 notch in the middle of each side, dividing the surface into quarters. Each quarter 

 contains a large sucker which is directed outward and upward. The apex of the 

 head is a smooth, rounded prominence with a small depression in the top. No 

 hooks are present. A fairly good idea of the shape of the scolex can be obtained 

 by placing two truncated pyramids base to base. One of the smaller bases will 

 represent the beginning of the neck, the other the prominence, while on the slope 

 just beneath this would lie the suckers. The notches seen in the anterior view of 

 the scolex form furrows down the four sides of the head, which gradually de- 

 crease in depth and vanish on the first few proglottids." 



Frequently the head is more globose than Benedict describes it. Such 

 heads are figured (Figs. 18, 19). The small apical papilla may not 

 always be seen but the furrows have been present in all heads examined 

 by me. Leidy 's figure of the head, reproduced (Fig. 134a), is somewhat 

 similar to mine. It, however, does not show the furrows. Two of Bene- 

 dict's figures of the head have been reproduced (Figs. 116, 117) for 

 purposes of comparison. 



