T. B. ROSSETER OX THE ANATOMY OF DICRANOT.^SIA CORONULA. 369 



the asci coalesces with its neighbours at the base ; thus the whole 

 is one homogeneous gland, from either side of which branches off 

 the distal and proximal uterine canals. 



The uterine canal (Fig. 5 b u, v) on leaving the shell-gland 

 is single, but becomes duplex, developing both distally and 

 proximally. Both of these canals run under the posterior margin 

 of each ovary, until arriving at the proximal and distal end 

 respectively. The distal end runs upwards to the centre of the 

 proglottis, forming pouches in its course to the lateral margin. 

 Whilst development is somewhat retarded in the proximal end, 

 it is accelerated in the distal, where the pouches rapidly develop 

 and become filled with ova, more especially at the lateral margins, 

 where one large orbicular pouch occupies the whole of the space 

 in the distal region. The testicular sac disappearing v^ery 

 early — in fact, it is the first organ to be absorbed — allows of 

 more space, and facilitates development in the distal more than 

 in the proximal end, where the receptaculum, with its superfluous 

 spermatozoa, is the last organ to be absorbed, being only 

 preceded by the strong muscular cirrus-pouch. The proximal 

 uterine canal confines itself to the narrow space between the 

 receptaculum and the posterior margin of the proglottis. The 

 pouches are thus for a time retarded in their development, and 

 circumscribed according to their environment ; but when the 

 cirrus-pouch and receptaculum are absorbed, and likewise during 

 absorption, they fill up the void caused by that act. The proximal 

 lateral pouch is likewise contracted (Fig. 19 ^? w p), and con- 

 tinues so in consequence of the genital cloaca remaining a cavity 

 in the uterine segments. There are fifteen pouches, nine proximal 

 and six distal, besides the lateral pouches. There is no uterine 

 pore, consequently they are blind pouches. 



The embryonic eggs and the hexacanth stage (Figs. 17, 18) of 

 the Tsenidse and Bothriocephalidae have been so lucidly explained 

 by Leuckart, Moniez, Yan Beneden, Blanchard, and Stiles, in 

 their published works, that I refrain from passing any remarks 

 respecting them in connection with this species. 



Description of Plates. 

 Plate 18. 

 Fig. 1. Inverted rostellum. — a, orifice; 5, retractor muscles;, 

 c, protractor muscles, x 260. 



