384 G. A. and W. G. MacCallum, 



very lax and made up of cells which are widely branched, giving 

 off Sheets of protoplasm which form a loose, wide meshed network. 

 The body of each cell is inconspicuous and contains a small nucleus. 

 It is faiiiy uniform throughout, although it shows condensations about 

 the various organs. 



The Excretory System. The water vascular System forms 

 conspiciious large marginal trunks which run through from segment 

 to Segment and are connected transversely in each proglottis by at 

 least one large cross Channel. Innumerable smaller branching 

 Channels are given off in every direction. The larger Channels 

 are lined by a structureless membrane which closely resembles 

 the cuticle. They are well snpplied with a musculature and 

 numerous cells resembling those of the skin. The smaller branches, 

 apparently devoid of musculature^ still have a radiating halo of the 

 glandulär cells. 



The Nervous System. No very minute study of the nervous 

 System could be made in the worm preserved in this way. But along 

 the margin occupied by the genital pores, there could be made out 

 three rather stout nerve trunks. Of these one runs dorsally and 

 one ventrally at the level of the cirrus, while the third lies in the 

 middle line just internally to the cirrus. These three trunks are 

 apparently connected more or less abundantly about the cirrus in 

 each proglottis. In the opposite margin only one nerve trunk can 

 be indistinctly made out. 



The Male Genitalia. The testis exists in each proglottis 

 in the form of numerous small oval or rounded lobules which are 

 collected in the anterior portion of the segment. principally toward 

 the margin which bears the genital pores. They do not extend far 

 toward the opposite margin nor posteriorly and are in reality extra- 

 ordinarily few in number when the enormous bulk of the worm is 

 considered. The process of spermatogenesis can be observed within 

 thera fairly well, inasmuch as they are seen to be made up of small 

 corapartments lined with syncytium - like areas and with deeply 

 staining cells from which there spring up sheaves of spermatozoa. 

 These are collected into the branching vasa efferentia which finally 

 reach, as the vas deferens, a large cirrus sac which lies medially in 

 the anterior part of the proglottis occupying a large portion of the 

 third of the segment near the genital margin. This sac is elongated 

 and somewhat folded upon itself as sliown in the sketch. Its walls 

 are quite thin and lined by a low, flattened epithelium, and one 



