61] PROTEOCEPHALIDAE — LA RUE 61 



La Rue (1911:475) listed this form among other Proteocephalus 

 species. Dr. H. B. Ward has very kindly loaned the writer his speci- 

 mens for study. More preparations have been made and from them 

 the writer has been able to secure additional data on this species. 



The type material in bottles 15, 16 and 42 was taken from the 

 intestine and oesophagus of Salmo sebago Girard, Sebago Lake, Me. Jy. 

 27 and Aug. 6, 1907. Other specimens which the writer has assigned 

 to this same species were taken by Dr. H. B. Ward from two specimens 

 of Cristivomer namaycush Walbaum (?), Lake Temagami, Ontario, in 

 August, 1911. These last are described separately. 



This is one of the smaller species of Proteocephalus. The observed 

 length is from 30-50 mm. for specimens which have ripe proglottids. 

 Proglottids are few in number and the segmentation is distinct. The 

 head is spheroidal but in many cases it is so greatly contracted that its 

 structure can not be determined. The head measures 0.300 mm. broad 

 by about 0.260 mm. long. The four suckers measure about 0.140 mm. 

 long by 0.110 mm. broad. The sucker cavity is quite deep. At the 

 apex of the head (Figs. 2, 3, 4) is a fairly well developed fifth sucker 

 which in well stained specimens shows an evident musculature and a 

 cavity. Ward (1910) reported only an end organ or vestigial fifth 

 sucker instead of a fifth sucker. When his specimen was restained and 

 mounted it showed a well formed fifth sucker. Characteristic fifth 

 suckers measure about 0.060 mm. in diameter. The neck is 1-1.5 mm. 

 long by about 0.21 mm. broad. It passes over quickly into the first pro- 

 glottids which are broader than long. Their breadth is about 0.090 mm. 

 The proglottids rapidly become quadrate or even longer than broad. 

 Ripe proglottids measure 0.84-1.4 mm. long by 0.18-0.35 mm. broad. An 

 end-proglottid is usually present and fertile. 



The common genital sinus is marginal, situated at the end of the 

 first Ys-% of the proglottid. Its position alternates irregularly. The 

 testes (Figs. 54, 55) number 44-60-70. Since these lie in two 

 layers the figure does not show all of them. In less mature proglottids 

 where the testes are much smaller and more distinct they can be counted 

 more readily. The testes measure 0.06-0.072-0.096 mm. long by 0.040- 

 0.050 mm. broad. The vas deferens (Figs. 53, 54, 55) forms a small 

 mass of coils in the middle of the proglottid. The larger part of the 

 mass is anterior to the cirrus-pouch, a condition not usually met with 

 in this genus. The cirrus-pouch which is rather heavy reaches Y~Y 

 across the proglottid breadth. Its length is 0.095-0.106 mm. and its 

 breadth 0.053-0.060 mm. The ductus ejaculatorius forms a coil or two 

 within the cirrus-pouch before passing over into the short straight cir- 

 rus which has not been seen protruded. On account of a lack of sufli- 



