236 ILLINOIS BIOLOGICAL MONOGRAPHS [236 



elongated segments the lobes of the ovary assume the form figured by 

 Marotel (Figs. 197, 198). 



The vitellaria are lateral, and made up of small follicles. The 

 vitelline ducts cross the ventral surface of the ovary instead of lying 

 some distance anterior to it as Marotel figured them. In mature pro- 

 glottids the uterus is a median tube. The early development of the 

 lateral pouches (Figs. 110, 198) may be traced as small somewhat 

 excentric bulbous enlargements of the median tube. This is not essen- 

 tially different from 0. filaroides and 0. perspicua. These enlarge- 

 ments may attain some size before any uterine eggs appear. In early 

 stages there is considerable resemblance to the condition shown in Mar- 

 otel 's figure (reproduced Fig. 198) of the ovigerous segment of 0. 

 calmettei. Later, how^ever, many of these pouches (Fig. 109) extend 

 toward the sides and the uterus resembles that of other species of the 

 genus. The walls of these pouches are not very easily observed so 

 Marotel may have overlooked them in his specimens. The pouches 

 number 24-35 on either side. Two to four or five ventral uterine pores 

 were observed in some of the riper proglottids. The uterine eggs in 

 the alcoholic material are surrounded by three membranes. The outer- 

 most very thin hyaline membrane measures from 0.024 to 0.026 mm. The 

 second, a thick and homogeneous membrane, measures 0.022 mm. The 

 inner membrane is thick, granular and more or less irregular in outline. 

 It measures 0.014 mm. while the six-hooked embryo measures 0.012 mm. 

 in diameter. Marotel (1899) states that the eggs are globular, with 

 two membranes, the outermost one being thin and membranous, 0.065 

 mm. in diameter, and the ,other, a homogeneous and somewhat thick 

 membrane, 0.024 mm. in diameter. This membrane corresponds in size 

 and description to the one which the writer calls the middle membrane- 

 He further states that the embryo is granular but does not give its 

 dimensions. 



This species varies from the 0. racemosa described by Schwarz 

 (1908) in the much larger size of the head, the larger size of the suck- 

 ers, and the relative prominence of the same. The number and arrange- 

 ment of the testes are radically different. In the length of the cirrus- 

 pouch, in the number of coils of ductus ejaculatorius they differ greatly. 

 In the size of the distal end of the vagina there is considerable differ- 

 ence. The character of the diverticula of the uterus is not the same. 

 In this species the uterus extends back to the ovary while in 0. race- 

 mosa as described by Schwarz it does not. The vitellaria are much 

 alike in character. This species is much smaller than 0. grandis. The 

 heads are of about the same size but not alike in shape. The relations 

 of cirrus, cirrus-pouch and vagina are different. There is a wide differ- 



