AVIAN CESTODES, 



437 



The paruterine part is about one-third of the total length of the 

 egg-holding receptacle. The walls of the paruterine body are 

 thick, and the fibrous-looking tissue has the strands running 

 along the greater length of the body. Externally it is plainly 

 marked off from the tissue of the medullary part of the proglottid. 

 The mass of calcareous bodies is as plain here as in the younger 

 paruterine organ ; but it has got a more definite coherence of its 

 own ; the corpuscles are imbedded in a tissue which forms a cap 

 to the paruterine organ and protrudes into the cavity of the 

 uterus behind. The suggestion is that of a valve which, however, 

 hinders the flow of ova into the paruterine organ rather than the 

 converse, which is what Avould be expected. 



Text-figure 5. 

 C 



— L 



Transverse section through mature proglottid, showing paruterine organ. 

 c. Central cavity of paruterine organ. I, Lateral water-vascular tube. 



The close relationship of the paruterine oi-gan to the uterus 

 is reminiscent of the conditions which obtain in the not nearly 

 allied genus Mesocestoides. In this Cestode, which has been 

 investigated by Hamann *, Fuhrmann t, and some others, the 

 uterus is divided into two regions Avhich form a continuous tube. 

 Posteriorly the uterus acquires thick fibro-spongy walls and serves 



* Zeitschr. f. wiss. Zool. 1885. 



t Swedish Exped. Egj'pt, pt. iii. 



