18 T. B. ROSSETER OX DREPAXIDOT.ENIA VENUSTA. 



It was filled in my specimen with apparently spherical cells, but 

 so closely were they packed, and so freely had they taken the 

 stain, that it was impossible, not only to define them, but also 

 to trace the enveloping capsule. The shell gland (Fig. 10, o) is 

 situated somewhat in front of, and contiguous to, the yelk gland 

 It is an oval organ whose long diameter is 0-026 mm., and breadth 

 0*013 mm. Its capsular membrane is apparently, like the 

 capsular membrane of the ovaries, structureless, taking no stain ; 

 while the cells, like those of the yelk gland, become so over-stained 

 that it is impossible to define them. 



As yet the generative organs of the Tsenise of birds have been 

 but imperfectly investigated, consequently we have not many 

 data to guide us. Yon Linstow, in his description of the anatomy 

 of Tcenia dejyi'essa, is silent, and makes no attempt in the sketch 

 of the generative organs to give us an outline of the course taken 

 by the ovarian ducts. It must not be thought I have over- 

 looked the work of either Feuereisen {Drep. fasciata) or Schmidt 

 (^Drei?. aiiatina). Unfortunately I am somewhat in the same 

 situation as Von Linstow and others : I cannot give an accurate 

 description of them. It is now, and always has been — even 

 Leuckart found it so — one of the most difficult things to trace the 

 course of these ducts, owing to the density of the parenchymatous 

 tissue. Even in examining my sections cut from the segments, 

 the ducts were found to be so severed and disconnected, that all 

 attempts to trace and fit them together was an impossibility ; con- 

 sequently all one can do is somewhat problematic, and this is far 

 from being satisfactory. But by putting together and fitting in 

 different portions of these ducts as they appear in the sections, and 

 taking one of the most perfect as a type, I have arrived at the 

 conclusion that these ducts take the course as given in Fig. 10, ?", J, 

 and k. The fertilising canal from the receptaculum seminis is 

 somewhat long. It crosses over the oviduct of the aporose ovary, 

 which runs vertically across the segment, dorsally to the uterine 

 canal, and makes a junction with the porose ovarian duct just 

 below its descending loop, thus forming a single ovarian canal ; the 

 fertilising canal joining it just below the ovarian junction, thus 

 forming one grand fertilising canal, and in which the small globu- 

 lar ova are fructified by the spermatozoa, and are conveyed into 

 the shell gland, there to commingle with the albuminous substance 

 poured into it by the efferent duct of the yelk gland, and by this 



