2O6 WINTERTON C. CURTIS. 



between these pseudo-proglottids of Ligula and the " anterior ' 

 proglottids of C. laciniatnin, I have made it clear that the greater 

 part, if not all, of these structures appearing at the anterior end 

 become true proglottids in the form I studied. 



Instances of irregularities like the occurrence of half proglot- 

 tids are noted by Braun, p. 1225, and dismissed as abnormalities. 

 Such a condition has recently been discussed by Child ('02) for 

 Monit'sia, but this again has nothing to do with the points I have 

 brought out for C. laciniatnin. The fact that no exception to the 

 typical method seems to have been recorded is to my mind justi- 

 fication for an extensive account of the mode of proglottid forma- 

 tion which I have observed in C. laciniatum and such an account 

 is therefore given in the section which follows. 



With the exception of the work by Linton, who described the 

 species, I know of nothing which has been published upon C. 

 laciniatum. This author in his original description (Linton, '86, 

 p. 474, PI. III.) speaks of small specimens and of the segments 

 occurring at either end in somewhat larger ones. The pos- 

 terior segments are, he says, "totally unlike those of the adult" 

 and " are evidently evanescent." It is, therefore, likely that 

 Linton had among his specimens the various stages which I have 

 described, but he paid little attention to them and hence his brief 

 paragraph does not bring out their significance. 



The " long-necked " specimens were also observed by Linton 

 and are referred to on several occasions. In his " Report of 

 Parasites Collected in 1898 " (Linton, '99) he records several in- 

 stances, and in an earlier paper ('89, on pp. 800-80 1) and PI. 

 VII., Fig. 4, he describes the "long-necked" forms and others 

 with a reduced number of segments in such a wav as to make it 



o * 



clear that he has seen all the stages up to the point where the 

 segmentation of the neck region begins. While not thinking 

 that they justify the erection of a new species he speaks of them 

 as a variety (longicolle) of C. laciniatnin and suggests that they 

 may represent the transition to another species. It is thus evi- 

 dent that Linton being interested primarily in the systematic 

 work, did not examine this point sufficiently to ascertain the real 

 significance of such stages. The importance of his observations 

 for my work is that they confirm my statement that a certain pro- 



