200 MR. F. E. BEDDARD ON A 



singly in the more pexnpheral regions ; more centrally tliey are 

 aggregated into bundles, the number of fibres being larger in the 

 deeper strata. In the largest I have counted 14 or 15 fibres. 

 Within this layer and bounding the medullary parenchyma is a 

 layer of delicate circular fibres. In older proglottids the number 

 of longitudinal fibres to a. bundle may be considerably greater and 

 the strength of the circidar layer has increased. This latter fact 

 is particularly to be noted in the segments which are nearly ready 

 for detachment. 



The water vascular tubes are the usual four longitudinal trunks, 

 of which — as is again usual — the dorsal is smaller and has much 

 thicker walls. The larger ventral tubes are connected by a rather 

 wide commissural vessel in each segment. The dorsal vessels are 

 apt to vary a little in their relation to the ventral vessels ; but 

 they are never superj)osed, i. e. directly dorsal and ventral to each 

 other. The dorsal vessel, in fact, lies to the inside of the ventral 



Text-fig. 23. 



Transverse section through an immature proglottid of Otiditcenia eupodotidis. 



The larger ventral water vascular tubes lie below aud rather to the outside 



of the smaller dorsal vessels. 



vessel, sometimes absolutely parallel with it and sometimes more 

 dorsally inclined. The capacity of the large ventral vessel tends 

 to vary ; I have seen it to be almost obliterated for a short space. 

 In the anterior segments of the body there is much less difterence 

 in calibre between the water vascular vessels than is to be seen 

 later. 



The testes of this tapeworm lie quite posteriorly in the segment, 

 and thus behind all the other paints of the generative system. 

 In sagittal sections of young proglottids in which the testes are 

 mature or nearly so, but in which the uterus is not yet much 



