396 T. B. ROSSETER ON HYMENOLEPIS ACICULA SINUATA, 



is occupied posteriorly by the reniform yelk-gland, 05 mm. 

 long and 0*013 mm. in diameter. The shell-gland lies proximal 

 of the receptaculum seminis, which it partially covers dorsally. 

 The oviducts are straight efferent ducts, deflecting only when 

 the fructifying canal and the duct of the shell-gland make a 

 junction with them. 



The ovarian eggs in uteri immediately after fertilisation are 

 orbicular, approximately 0*004 mm. in diameter. 



The uterus (Figs. 6-9) in its early stage is an elongated sac and 

 occupies transversely 0*473 mm. of the segment ; but as the six- 

 hooked brood develops and becomes perfected the segment is filled 

 and becomes a uterine sac. Its boundary walls, which are rounded 

 proximally and distally, are the longitudinal dorsal and ventral 

 excretory canals. 



The ovum containing the perfected six-hooked brood is com- 

 posed of three envelopes (Figs. 12, 13), the outer one being an 

 elongated oval, its polar axis 0*091 mm. and its equatorial 

 diameter 0*034 mm. The lateral borders of the second envelope 

 are drawn out or constricted, 0*074 mm. by 0*027 mm. ; the third 

 envelope is ovular, and encloses the embryo 0'047 mm. by 0*017 

 mm. ; whilst the embryo or hexacanth stage is 0*041 mm. by 

 0*014 mm. The embryonic hooks are 0*013 mm. in length. 



The above is but a brief description of the genitalia as they 

 exist in the segment. 



The method of propagation (Fig. 16) in this tape-worm presents 

 such peculiarities in contradistinction to any species of Taenia 

 with which I am acquainted that it requires special elucidation, 

 and in order to do this I must of necessity refer back to the 

 anatomical details of the male genital apparatus. Thus in the 

 above description it will be noticed that I have refrained from 

 designating the male' copuhitory organ by the usual appellation 

 of cirrus with its concomitant sheath and pouch (or bursae 

 copulatrix), simply because, as will be seen in the sequel, in this 

 instance no such organ physiologically exists. The minuteness 

 and insignificance of the male organ of fructification renders it 



