AUT. 7 CESTODE PAEASITES OF BIBDS LINTON 41 



RECORD OF COLLECTIONS 



Colymhus auritus: 



1905, December 25. — Numerous scoleces with short strobiles, 1.5 

 mm., more or less, in length. 



1906, December 8.— Three. 



1914, April 16. — Numerous; most of them exceedingly filiform 

 anteriorly, length about 40 mm.; others stouter, maximum 

 60 mm. 

 Colymhus KoTboelli^ new host : 



1904, February 25. — One, slender and thread-liko. Length, in 

 formalin, 22 mm. ; diameter of scolex 0.22. 

 (U.S.N.M., Helm. Coll. 7879.) 



HYMENOLEPIS ROSTELLATA (Abildgaard) 

 Figures 139-142 



Scolex. — Varying in shape, but in most cases bluntly rounded with 

 subcircular suckers; rostellum as long, or longer than the scolex, 

 when fully extended, more or less abruptly enlarged at the apex, 

 which bears a single circle of 10 hooks, from 0.048 to 0.06 mm. in 

 length. The sheath of the rostellum is conspicuous, muscular and 

 extends into the neck. Diameter of a scolex in balsam about 0.30, 

 of sucker about 0.14; length of everted rostellum 0.22, diameter, 

 middle, 0.04, at apex 0.09. 



Strohile. — There is a short neck, or unsegmented portion, which 

 is usually narrower than the scolex. The proglottides, which begin 

 near the scolex as fine transverse lines, remain short and closely 

 crowded together for a greater or lesser distance. There is a great 

 variety of forms exhibited in the strobiles. Some are rather 

 thickish, with very closely crowded proglottides, the breadth many 

 times the length; others are slender, filiform with proglottides be- 

 coming as long as, or longer than broad. It would appear to be 

 impossible to regard these varying forms as belonging to the same 

 species if it were not for the fact that similar and as great A^ariations 

 may occur in the same strobile. Genital pores unilateral. The 

 walls of the genital cloaca are thick. The cirrus-pouch is large, 

 subcylindrical, and when not curved extends nearly, if not quite, to 

 the anti-poral excretory vessels. The three testes are relatively 

 large, one on the poral and two on the anti-poral side of the ovary. 

 The ovary is lobed, and may attain a breadth more than one-third 

 that of the proglottis. The much smaller vitelline gland lies on 

 the median line behind the ovary, is more compact than the ovary, 

 but was seen to be distinctly lobed in some of the proglottides. 



The following account of the anatomy of a proglottis is based on 

 an examination of a series of transverse sections. The cirrus emerges 

 10582—26 4 



