59] PROTEOCEPHALIDAE — LA RUE 59 



broad. Ripe proglottids much longer than broad. Length of same 

 0.84-1.4 mm., breadth 0.18-0.35 mm. End-proglottid present and fertile. 



Genital sinus marginal, irregularly alternating, situated at end of 

 first %-% of proglottid. Vagina usually anterior and dorsal to cirrus- 

 pouch, rarely posterior. Testes 44-60-70 in number, arranged in two 

 layers between vitellaria. Length of same 0.06-0.096 mm., breadth 

 0.04-0.05 mm. Vas deferens a small mass of coils anterior to cirrus- 

 pouch. Cirrus-pouch 0.095-0.106 mm. long by 0.053-0.060 mm. broad, 

 reaching l /z-y± across the proglottid breadth. Ductus ejaculatorius 

 forming one or two coils in cirrus-pouch. Cirrus short and straight. 

 Vagina never crossing cirrus-pouch. Sphincter vaginae and receptacu- 

 lum seminis not seen. Ovary bilobed, posterior. Lobes short, thick, 

 free ends of same frequently pressed posteriad and together. Vitellaria 

 sparse, follicles small. Uterus with 10-14-16 lateral pouches on either 

 side. Eggs not observed. 



Habitat: Intestine and esophagus of Salmo sebago Girard (type 

 host), Sebago Lake, Me. (type locality) ; intestine and pyloric coeca of 

 Cristivomer namaycush Walbaum (?), Lake Temagami, Ontario. 



Type: Material in bottles 15, 16, 42, in Professor Ward's collec- 

 tion from Sebago Lake, Me., summer of 1907, and slides from this 

 material. 



Ward (1910:1185-1187) first described this species which he had 

 found in the Sebago salmon. Ward's description follows. 



"Proteocephalus pusillus nov. spec. — Adult cestode with short strobila, meas- 

 uring only 30 to 50 mm. in length. Proglottids scanty, segmentation distinct. 

 Head much contracted. Neck 1 to 1.5 mm. long by 0.21 mm. broad. First pro- 

 glottids 0.09 mm. broad changing gradually until in mature proglottids the length 

 greatly exceeds the breadth. Ripe proglottids measure 0.84 to 1.4 mm. long by 0.18 

 to 0.35 mm. broad. Terminal proglottids present and fertile. Sexual organs 

 typical for Proteocephalus ; uterus median, with 10 to 14 lateral outpocketings on 

 either side. Testes numerous, within vitellaria. Genital pore lateral, one-third to 

 two-fifths of length of proglottid from anterior margin of same. Ovaries bilobed, 

 median isthmus indistinct, anteroposterior diameter nearly equal to breadth of 

 both lobes. Only a few specimens obtained from a single host species, Salmo 

 sebago. 



"This species approaches most nearly to P. occllata and P. percae among 

 known species. Unlike the new species, however, both of these older forms have 

 a fifth sucker, a few lateral uterine outpocketings, a longer neck, differently shaped 

 ovaries, and markedly different proglottids. 



"In specimens with developed proglottids the head was so much contracted 

 or distorted that any special description would be of little value. One could 

 easily observe the general features characteristic of the genus. There was no 

 well developed terminal or fifth sucker, and the end organ, which is known to 



