306 T. B. ROSSETER OX HYMENOLEPIS FARCIMINALIg. 



and in close proximity to, the yelk-gland. Its stalk or duct is 

 very pronounced, as it arches upwards over the yelk-gland and 

 forms a junction with the yelk-duct, into which it pours its 

 secretion. The whole of these ducts are so intermingled as to 

 make them very difficult to trace, except by staining and careful 

 manipulation. 



The uterus in its early inception is dendritic (Fig. 1, d.). It 

 lies in the median transverse plane of the segment proximal and 

 distal, and dorsal to the ovaries. As the racemes of the ovaries 

 empty their contents they are absorbed and the uterus takes 

 their place in the proglottis. One would imagine that the involu- 

 tions of the dendritic papillae on each side of the canal would 

 develop into a pouch or sac, instead of which the developing of 

 the ova into the six-hooked brood causes the involutions to swell 

 up on a level with the papillae, and thus the whole forms a 

 common uterine sac, characteristic of the genus Hymenohjns 

 (Weinland) (Fig. 1, '<?.). The uterus is confined to 0*7 mm. from 

 each lateral border.* The uterine eggs (Fig. 4) or six-hooked 

 brood are sub-spherical, approaching an oval. Their polar axis 

 or length varies from 0*05 to 0*076 mm., and their equa- 

 torial diameter is approximately 0-063 mm. They possess three 

 envelopes. The space between the outer and middle envelope is 

 0*014 mm., and between the second and third 0*007 mm. ; whilst 

 the embryo is 0*034 mm. long and 0*27 mm. in diameter. These 

 figures of size and space must not be taken as fixed quantities, 

 but rather approximately, as they vary very much in different 

 examples. The embryonic hooks are 0*013 — 0*015 mm. in length. 

 The outer envelope is smooth and diaphanous, and the inter- 

 vening space between it and the second envelope is filled with 

 a glairy matrix. The middle envelope is somewhat pellucid and 

 wrinkled, the wrinkling being caused by the cellular vitelline 

 detritus, which fills up the narrow space between it and the third 

 envelope. The third or embryonic envelope is ovular and dia- 

 phanous. It is conical at each pole. There is apparently no 

 capsule, but by the aid of a y^-ineh oil immersion objective each 



* There is sometimes an exception to this, the uterus extending itself in 

 1 he form of a pouch at the distal anterior lateral border of the segment. 



