ART. 7 CESTODE PAEASITES OF BIRDS LINTON 31 



This material comprises a number of fragments of strobiles, rep- 

 resenting two individual chains, 33 and 52 mm. in length, respec- 

 tively. A characteristic of these strobiles is the variety of shapes 

 which the proglottides have assumed in different regions. Thus, in 

 one strobile, the anterior portion for about 9 mm. consists of proglot- 

 tides which are at first distinct and somewhat wedge-shape, length 

 0.25 mm., breadth 0.35. These are followed by proglottides 0.28 in 

 length and 0.42 in breadth. At the posterior end of this 9 mm. 

 portion the length of the proglottides has decreased to 0.18 and the 

 breadth increased to 0.63. At this point the character of the proglot- 

 tides changes abruptly. For a distance of 3 mm. the proglottides 

 are closely crowded, the length being about 0.06 and the breadth 

 1.12. Beyond this thickened portion the proglottides again become 

 wedge-shape, length 0.35, breadth at anterior end of proglottis 0.56, 

 at posterior end 0.75. This condition is maintained for about 8 mm. 

 The remainder of the strobile is made up of proglottides which 

 become broader and shorter. At about the fourth proglottis from 

 the posterior end the length is 0.28, the breadth 1.54. Genitalia 

 begin near the anterior end. The cirrus-pouch and testes show dis- 

 tinctly in the proglottides, which immediately precede the thickened 

 portion. The latter is rather opaque, the testes and rudiments of the 

 female genitalia are crowded into a laterally elongated mass which 

 occupies the middle third of the breadth of the proglottis. In the 

 first distinct segments behind the thickened portion the testes are 

 much larger than they are where last seen in front of the thickened 

 portion. While in the last segment in front of the thickened portion 

 the diameter of a testis is barely 0.07 mm., the diameter of a testis 

 in the first distinct segment back of the thickened portion is 0.15 mm. 

 Moreover, the ovary and vitelline gland, which were not distinguish- 

 able in front of the thickened portion, are clearly shown in the 

 proglottides which succeed the thickened portion. The ovary in- 

 creases in size and becomes more lobed in succeeding proglottides. 

 The posterior proglottides are again much crowded, and the anatomy 

 is difficult to interpret. Essentially the same characters are shown 

 in the other strobile. In maturing proglottides the ovary increases 

 in size and in number of lobes, while the testes decrease in mass, and 

 what seems to be a relatively spacious seminal vesicle appears poste- 

 rior to the median end of the cirrus-pouch. The genital pores are 

 unilateral. The cirrus-pouch is long-pyriform, largest at its inner end. 

 In younger segments its inner end is near the anterior border not far 

 from the median line. Thence it passes posterio-laterad to the mar- 

 gin, where it opens at the genital cloaca, a little in front of the middle 

 of the length of the segment. The testes are three in number and 

 lie near together at the middle portion of the posterior end of the 



