38 T. B. ROSSETER ON THE TAPE-WORMS 



those of Krabbe's T. nitidulans. The neck (Plate 6, Fig. 1) is very 

 short, 0*135 mm. ; thus stabilisation commences immediately, 

 as it were from the base of the scolex. The composition of the 

 strobila and the formation of the segments will be best under- 

 stood by reference to the sections of the strobila given in Figs. 

 2 — 13, which are a facsimile of those of a type specimen. The 

 organs of generation do not commence to develop until 8*150 mm. 

 of strobila have been budded off from the scolex, and then the 

 median testis appears as a small group of cells. 



Both male and female genital pores are situated on the extreme 

 proximal lateral border of the segment, the male anterior to the 

 female, both being raised prominently from the proglottis like two 

 papillae (Figs. 11 and 12). 



There are three orbicular testes (Fig. 11, ttt), situated medially, 

 proximally, and distally in the segment. They are enclosed in a 

 hyaline membrane which is unaffected by staining, and have a 

 mean diameter of 0*034 mm. The efferent ducts of the proximal 

 and distal testes make a junction with the emerging duct of 

 the median testis, and thus form a common efferent duct, which, 

 running upwards distally and curving round, forms the narrow 

 distal duct of the vesicula seminalis. The vesicula seminalis is a 

 pyriform sac 0*186 mm. long, with a diameter at its rounded end 

 of 0*017 mm., and is situated in the distal anterior portion of 

 the segment. The vas-deferens, which emerges from its proximal 

 end, is short, undulating, and makes a junction with and enters 

 the cirrus-pouch. 



The cirrus-pouch (Fig. 11, cp) is long and attenuated, its 

 diameter in its swollen or median part being 0*017 mm., whilst 

 its extreme length is 0*185 mm. Its proximal end is elongated 

 into a hollow cone, from the orifice of which the cirrus emerges. 



The cirrus is a short spinous rod, 0*031 mm. long and 

 0*007 mm. in diameter. The spines are but faintly resolved 

 with a J-in. objective. The distal portion of the cirrus is a 

 long coiled duct, the vas-deferens interior. The pouch is enclosed 

 by a comparatively large oval light-refracting sac (Fig. 11, pgs), 

 characteristic of this species, and somewhat analogous to a 

 similar organ in If. nitida. Krabbe calls it the " oval-cirrus- 

 blaeren." I have already shown in my description of the 

 genitalia of H. nitida the error Krabbe made in denominating 

 it as such, when in reality in that species it is the female recep- 



