190 



S. J. JOHNSTON. 



by J'agerskiold in S. expansus shows 

 some differences. Text figure 1 is a 

 projection on squared paper, made 

 from a series of transverse sections 

 of the ventral aspect of the excretory 

 vesicle and the two chief vessels. 

 This vesicle differs from that of the 

 African form chiefly in the fact that 

 the main stem, just behind the 

 posterior testis, divides into two 

 branches which unite again in front 

 of it, instead of the right branch 

 ending blindly. Then in the space 

 between the two testes these two 

 wide branches form a network from 



Fig. l.-Excretory sys- wMch > at the leVel ° f the P°Sterior 



-tern of Scaphanocephaius e nd of the anterior testis two wide 



australis. Ex. v. excretory , _ 



vesicle; E. collecting ves- branches emerge, one passing round 



flak. Projection on squared either gide of th t ti 0]Qe of 



paper from a series of trans- 

 verse sections. The names these branches ends blindly and the 



of the organs that form , . . 

 easily recognisable features exact arrangement seems tO be SUb- 

 are written down in the j ect t0 variation, for in one of my 



position in which the organ 



occurs. specimens it is the right which so 



ends, while in another it is the left. 



The remaining branch, behind the ovary and receptaculum 

 seminis, divides into two long arms which run forwards, 

 widely separated from one another by the loops of the 

 uterus, but converging in front of this so as to come almost 

 into contact in front of the ventral sucker, where they end 

 as more or less wide pockets. Bach of these pockets gives 

 off a tube that runs out fairly straight at right angles to 

 the long axis of the body, into the lateral wings: these 

 transverse tubes are excretory vessels, as distinct from the 

 vesicle, their walls being of a character entirely different 

 ifrom those of the latter. They pass to the outer side of 



