BREPANIDOTAENIA TENUIROSTRIS. 405 



those of Dicranotaenia coronula. The observations made on these 

 glands, and the conclusions drawn as the result of those obser- 

 vations — read before the Quekett Club in my paper on the 

 generative organs of Dicranotaenia coronula on April 20th, 1900 — 

 apply also to those of the present helminth. The ovarian ducts 

 have a diameter of 003 mm., becoming reduced at their junction 

 with the fructifying canal. The porose ovary has a length of 

 0*185 mm., and the aporose 0*169. The latter is narrower and 

 more compressed than the former. 



The shell gland (Fig. 5, s.g.) is situated medio- vent rally on 

 the posterior border of the segment between the two ovaries. It 

 is a reniform gland 0*089 mm. long, and its apical axis 0*04 mm. 

 The secretive cells of this gland and those of the ovaries both 

 readily take, and are deeply stained by haematoxylin. 



The yelk gland (Figs. 5 and 7) is unique in its character ; in 

 fact, it may be looked upon as a distinctive characteristic of this 

 species of tape-worm, for instead of being situated as it usually 

 is in other species (viz. medio- ventrally between the ovaries and 

 posterior to the shell gland), in this case it lies in the median line 

 of the proximal third of the proglottis close under the vesicula 

 seminalis and dorsal to the vaginal canal. It is a long club-shaped 

 gland 0*086 mm. long and 0*03 mm. wide. The efferent duct is a 

 long tortuous canal, and makes a junction with, and empties the 

 secreted yelk into, the shell gland. This is demonstrable in those 

 segments in which the organs of generation, having fulfilled their 

 mission, are gradually wasting away, and they contain not only 

 exhausted and partially exhausted yelk glands, exhibiting their 

 cuticular structure, but likewise those yelk glands whose 

 secretive substance has passed into a thick, tough, cheesy, and 

 in some cases a brittle, condition (Fig. 7). In such the efferent 

 duct, losing its support in the surrounding tissue, which has become 

 transformed into the already forming uterus, breaks up into 

 pieces, thus exposing the coagulated secretion within the duct. 

 This gland is the last organ of generation to form within the 

 proglottis, commencing its evolution from the cellular tissue of 

 the segment about 22*600 mm. from the scolex. 



I regret that, owing to my specimen being deficient below 



JouRN. Q, M. C, Series II.— No. 52. 27 



