16 G-H Canadian Arctic Expedition, 1913-18 



quadrate or somewhat broader than long, 0-72 in width by 0-48 to 0-60 in 

 length; ripe joints quadrate to somewhat longer than broad, 0-84 to 1-00 long 

 by 0-68 broad; terminal segment pointed. 



Genital organs as in genus. Genital pore marginal on a very low papilla, 

 about two-fifths of length of proglottis from anterior border of same, irregularly 

 alternating from right to left. 



Testes arranged in two partial layers between the vitellaria, 50 to 70 in 

 number, spheroidal in shape, 55 to 100/u in diameter. Vas deferens a mass of 

 coils in middle of segment, 0-16 to 0-20 in diameter. Cirrus-sac, 0-36 to 0-40 

 mm. in length by 0-14 to 0-18 in diameter, extending to near the median line of 

 the segment, lying at right angles to margin of same. Cirrus straight in cirrus- 

 sac. 



Vagina opens anterior to cirrus-sac, lies ahead of it for two-thirds of its 

 (cirrus-sac's) length and crosses it ventrally at the beginning of the inner one- 

 third or one-quarter of the same. Small vaginal sphincter, 50;u in diameter, 

 near its opening. Vagina 18/i in diameter just Avithin sphincter, 15ju where it 

 turns posteriorly. Receptaculum seminis anterior to ovary, 20 to 30m in diam- 

 eter; spermiduct, 9 to 12yu. Ovary bilobed, lobes ovoidal; whole organ 0-58 

 mm. in width by 0-12 in length. Oocapt, 25 to 30yu in diameter; oviduct, 25yu. 

 Uterus with 6 to 9 diverticula on each side, anterior end broadly rounded, whole 

 organ, 0-48 to 0-54 mm. in width by 0-64 to 0-70 in length. Uterine pore 

 usually single (sometimes in the form of two separate openings). 



Embryo, 20 to 25/x in diameter. 



Type host. — Salvelinus marstoni Garman, red Canadian trout, in posterior 

 portion of intestine, in company with Ahothrium crassum and Diphyllobothriuni 

 sp. larv. (vide supra). 



Type locality. — Lake at Bernard harbour. Northwest Territories, Canada; 

 C.A.E. Stations 42o and 42r. 



Collected by Mr. Frits Johansen, October, 1915. 



Cotypes are deposited in the Victoria Memorial Museum, Ottawa, Canada, 

 (Annelids, etc., Catalogue No. 82), and in the collection of the writer at Chicago, 

 Illinois, U.S.A. 



This species resembles P. filicoUis (Rud.) and P- esocis (Schneider) as 

 described by LaRue (1914) in that the testes are arranged in two partial layers 

 and the latter in that the cirrus-sac extends about half way across the proglottis, 

 l3ut it otherwise represents an aggregate of characters, many of which individually 

 or in small groups resemble those of other species of the genus. 



Order III Cyclophyllidea Beneden 



Family I DILEPIDIDAE Railliet et Henry 1909, e.p. Liihe 1910 



Subfamil3' DILEPIDINAE Railliet et Henry 1909 



Genus I Lateriporus Fuhrmann 1908 



Lateriporus geographicus, sp. nov. 



(Figs. 9, 13, 14). 



Specific diagnosis. — -With the characters of the genus. Medium sized 

 cestodes at least 172 mm. in length by 2- in diameter. Scolex almost spherical, 

 0-56 mm. in length by 0-62 in width. Rostellum stout and truncate, at least 

 0-16 mm. in length by 0-30 in diameter; nature and arrangement of hooks not 

 observed. Suckers unarmed, not especially prominent, nearly circular in outline, 

 0-28 mm. in length by 0-24 in width. Unsegmented neck about 1-1 mm. in 

 length by 0-45 in diameter, constricted to 0-28 mm. immediately behind the 

 scolex; shows many transverse rugae closely resembhng the foremost segments 



