18 G-H Canadian Arctic Expedition, 1913-18 



24/z in L. &.). The specific name chosen has reference to the map-like contour 

 of the uterus. 



Genus II Choanotaenia Railliet 1896 



Choanotaenia passerellae, sp. nov. 



(Figs. 10, 15.) 



Specific diagnosis. With the characters of the genus. Small oestodes at 

 least 20 mm. in length by 0-95 in maximum breadth. Scolex small, conoidal, 

 aUmt 0-14 mm. long by 0-20 wide. Rostellum cylindrical and spheroidal at 

 tip, 72/i wide; nature and arrangement of hooks not observed. Suckers 

 i manned, prominent especially posteriorly, circular in outline, at least 90/x in 

 diameter. Unsegmented neck about 0-16 mm. long by 0-20 wide. Anterior 

 proglottides very short; middle infundibuliform and much narrower anteriorly 

 than posteriorly; hindermost, 1-72 mm. in length by 0-95 in width, with some- 

 what convex lateral borders and more nearly the same width at their anterior 

 borders as at their posterior borders. 



Genital pores irregularly alternating, located two-ninths of length of segment 

 from its anterior end. Vaginal opening posterior to and on the same horizontal 

 plane with that of cirrus. Genital cloaca unarmed. 



Testes massed in the posterior two-fifths of the segment and surrounding 

 the vitelline gland, 20 to 25 in number, each with maximum diameter of 75/*. 

 Coils of vas deferens median and close to anterior border of segment, 0-15 to 

 0-20 mm. in diameter. Cirrus-sac, elongated, spindle-shaped, 0-25 to 0-27 

 mm. in length by 56/z in diameter. Vas deferens coiled proximally in cirrus-sac, 

 straight distally. Cirrus at least 55 to 70/i in length by 18ju in diameter, armed 

 with small, stout pines. 



Vagina lies posterior to cirrus-sac and after crossing the large ventral 

 excretory canal is dilated to form an elongated seminal receptacle, the proximal 

 end of which, almost median in position between the ovarian lobes, may be as 

 much as 70/x in diameter when filled with spermatozoa. The bilobed ovary, 

 0-32 mm. in length by 0-36 in width, occupies the whole of the transverse 

 diameter of the segment between the excretory canals. Each lobe is composed 

 of tubular lobules radiating from a median isthmus about 0-08 mm. in length; 

 that situated on the side bearing the genital apertures is much shorter than the 

 other. Shell-gland median, compact, almost spherical in shape, 70/z in length 

 by 45 in width. Vitelline gland median behind the shell-gland, compact, irregu- 

 lar in shape, 130/* in length by 110 in width. The gravid uterus fills most of the 

 segment, extending beyond the excretory canals on each side. 



Eggs almost spherical in shape, 25 to 30/i in diameter, contents (before 

 cleavage had set in) at least 20ju. 



Type host. Passerella iliaca (Menem), the fox sparrow, in the stomach, 

 in company with Aploparaksis elisae Skrjabin. 



Type locality. Teller, Alaska. 



Collected by Mr. Frits Johansen, August 3, 1913. 



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

 (Annelids, etc., Catalogue No. 84), and in the collection of the writer at Chicago. 



Although I did not observe the nature and arrangement of the hooks on the 

 rostellum of this form, these having evidently been all torn away from the only 

 two scolices in the small lot of material collected, I consider this species to be 

 new, since in other regards it differs more or less considerably from the species 

 of Choanotaenia, the descriptions of which were available. It closely approaches 

 however, C. parina (Dujardin 1845) which is found in Passer domesticus (L.) 

 and other passeriform birds, as shown by the following excerpts from the, brief 

 description by MaroteJ (1899) of that species: 



