336 LKWIS IIKXkY OOUCIH. 



The segments are always uiuch broader than long, and 

 usually also much broader than thick (except in the posterior 

 portion of the strobila). The extreme brevity of the segments 

 causes the genitalia at male maturity all to lie in one plane, 

 single transverse sections 4/.t thick then often presenting the 

 whole anatomy, as in a diagram. AVhen the paruterine 

 organ develops in the terminal portion of the strobila, the 

 anterior and posterior surfaces of the segments are no longer 

 flat, but are arched above the paruterine organ, bulging 

 thus into the segments nearest in front and behind, and 

 receiving depressions from the pressure of the paruterine 

 organs of the segments anterior and posterior to it (fig*, o). 

 Except at the posterior end of the strobihi, the hind end of a 

 proglottid does not surround the anterior end of the next. 



The genital pores alternate irregularly ; they are very 

 slightly developed as compared to those of the Stilesiic. 



Calcareous corpuscles are extremely rare; two only have 

 been observed in over one hundred series of sections. 



The longitudinal muscles are apparently arranged in 

 bundles of twenty-four or more, and a few solit.iry muscles 

 are seen close to the subcuticula. The " bundles" are, how- 

 ever, not distinct on horizontal sections (see p. o52). The 

 transverse and the dorso-ventral muscles are very Aveak. 



The ventral canals are very strongly developed in the 

 strobila; their diameter varies from 72 ju at the apex of the 

 scolex to 160 X 240^ at 70 cm. from the scolex. The dorsal 

 canal measures 72 fx at the apex, 32 fx at the base of the scolex. 

 Its lumen is almost obliterated at 40 cm. from the scolex. 



The course of the canals, in the scolex is described 

 furtiier on. 



'J^hc first traces of the "-enital oro-ans are seen at 1 cm. from 

 the scolex. Tlie testicles are recognisable at 12 cm., the 

 ovarium appears at 40 cm., male sexual maturity is reached 

 at 70 cm.; at this stage tlie uterus begins to develop. The 

 paruterine organs commence to develop at 90 cm. 



There are three to six testicles on each side of each of the 

 ventral canals, leaving a great gap in the middle of the segment 



