AN ABNORMAL CESTODE PROGLOTTID. 157 



literature of the subject is considerable. The only case, how- 

 ever, which at all resembles the subject of this sketch, that I 

 find in the literature of the subject, to which I have access, is the 

 one recorded by Blanchard for Tcenia saginata {Bulletin de la 

 Societe Zoologique de France, 1890, XV., 166-168, and reprinted 

 in Pr ogres Medical, July, 1 894). 



My friend Dr. Stiles informs me that, while he has repeatedly 

 found abnormalities in cestode segments, he has not made any 

 record of any cases such as is described in this paper. 



On account of the unique character of this abnormality, there- 

 fore, and for purposes of comparison I reproduce Blanchard's 

 figure (Fig. 2). 



In Blanchard's specimen the ovaries and vitelline glands are 

 at opposite ends of the abnormal segment ; the testes are con- 

 tinuous along the lateral margins ; the reproductive apertures 

 are on opposite lateral margins ; the uterus is common to both 

 parts. At about one third of the length from the anterior end 

 there is a transverse incision which reaches to the median line, 

 and is followed on its side by a perfectly normal segment. If 

 this incision were to extend somewhat diagonally across, so as 

 to reach the other margin behind the reproductive aperture, 

 there would then be a single inverted segment intercalated 

 between two normal segments. 



It should be stated here that the abundance of material found 

 in the summer of 1905 furnishes additional data, which will make 

 it necessary to separate the two varieties noted in the original 

 description (see Bulletin of the United States Fish Commission 

 for 1899, p. 298) into two distinct species. 



The abnormal segment belongs to the larger variety which 

 will retain the name C. occidental. 



WASHINGTON AND JEFFERSON COLLEGE, 

 December I, 1906. 



