114 Transactions of the Royal Canadian Institute, [vol. x. 



cortical or contractile layers divided up into a number of fibrils, which, 

 however, still retain their connections with the protoplasmic substance 

 of the myoblasts. 



The nervous system consists of two chief strands, situated laterally 

 in the medullary parenchyma ("Markschicht") and united beneath the 

 tip of the scolex to form a very small ganglionic ring. Connected with 

 these are eight collateral strands, four located around each chief strand, 

 which appear in the jointed portion of the strobila only. 



The excretory system is composed of one large median vessel, — the 

 equivalent of the usual dorsal pair — and two smaller, situated laterally 

 and ventrally. All of these unite in the scolex to form a median vesicle 

 accommodated in the hollow behind the nerve-ring. Foramina secundaria 

 and flame-cells are fairly numerous, but their connections are difficult 

 to trace. 



The genital organs are simple, on the whole resembling those of 

 Dibothriocephalus latiis (Linn.). The genital apertures are all situated 

 on the ventral surface in the median line, that of the vagina close behind 

 the cirrus-opening towards the anterior end of the proglottis, that of 

 the uterus much farther back and evidently a temporary aperture only. 

 There is no distinct genital atrium or cloaca. 



The testes are all in one plane and separated into two lateral fields by 

 the median excretory vessel. Opposite the genital ducts both testes and 

 vitelline glands separate dorsally and ventrally to leave clear "middle 

 fields". The vas-deferens, which courses in the median line dorsal to the 

 uterus-sac, is provided, at its posterior end near the middle of the pro- 

 glottis, with a sperm-reservoir, and with a large almost spherical seminal 

 vesicle situated immediately behind the cirrus-pouch. The latter is 

 spheroidal in shape, simple in structure, and contains the continuation 

 of the vas-deferens, divided into three regions, an ejaculatory duct, a 

 second seminal vesicle and the cirrus. The cirrus is lined with cuticle 

 in which there are small stout spines and around which there is a series 

 of well developed circular muscles. 



The vagina, the entrance to which is also lined with cuticle and 

 supplied with a sphincter muscle, courses ventrally and expands within 

 the "generative space" to form a seminal receptacle, sharply separated 

 from the very small and short continuation, the spermaduct which unites 

 with the oviduct in the usual way. The ovary and shell-glands are 

 median and respectively ventral and dorsal. The yolk-glands are com- 

 posed of numerous follicles, arranged cylindrically around the testes, — 

 both within the longitudinal muscles of the parenchyma. There is a 

 large yolk-reservior, situated in the generative space. The uterus is 

 divided into two distinct portions from the earliest appearances in the 



