425] 



PSEUDOPHYLLIDEA FROM FISHES— COOPER 



137 



the segments did not seem to be much affected. In addition it should be noted 

 that besides being "not so closely crowded" the segments at the extreme 

 posterior end of this strobila are relatively much narrower, as a matter of 

 fact, only two-fifths as wide as the widest part of the strobila. This seems 

 to be quite comparable to the elongation of the posterior end of Schistocephalus 

 when it reaches the final host and matures. 



Another important characteristic, which should be mentioned here in deal- 

 ing with the external features, is that "In alcoholic specimens a dark m.edian 

 line will be noticed extending from the posterior end to the middle or anterior 

 third of the strobila. This is due to the centrally situated ovaries [uterus- 

 sacs] which are crowded with eggs;" while "a median furrow on one of the 

 lateral [surficial] faces of the body begins toward the anterior and becomes 

 punctate towards the posterior region, where the minute lateral genital aper- 

 tures become visible in a zig-zag row. " 



The following table gives comparative measurements of several strobilas, 

 the first columns being the data given by Linton: 



Concerning the cuticula Uttle can be said, since the material studied was 

 very poorly preserved. Only in sections of a very young strobila was it seen 

 with any degree of certainty. There it was found to be about 4.5jLt in thick- 

 ness, and divided by differences in degree of staining into a dark cuter one- 



