844 DR. F. E. BEDDARD ON A 



is, however, on either side of the body and running parallel with 

 the main nerve-cord a second and a third nerve-cord (see text- 

 fig. 119, N) which lie above and below the former and at some 

 distance from it. These accessory nerve-cords appear to be 

 exactly like the main nerve-cord in structure and are situated 

 at the boundary of the medullary and cortical regions, a trifle 

 nearer to the middle of the segment. In sagittal sections the 

 supplementary nerve-cord is very obvious and is seen to be con- 

 nected with the main trunk by numerous (7 or 8) transvei^se 

 cords in each segment, which produce a ladder-like appearance. 

 Thex'e is an obvious likeness here to Bertiella, in which genus the 

 nerve- cord also consists of three separate strands, and to Dioico- 

 cestus, where the cords are wider apart. They are, however, much 

 closer together in Bertiella than in the present worm. I have 

 not observed this arrangement of three nerve-cords in the supposed 

 immature form already described. But it is to be observed that 

 the main cord is there almost as wide as the medulla, thus leaving 

 no room for the accessory cords which may be split oif later. 



§ Sexual Organs. 



In the middle region of the body and possibly for some way in 

 front (I have not examined sections just in front of the mid- 

 region) the proglottids are full of ripe eggs. I have examined 

 these proglottids in sagittal as v/ell as in transverse sections. The 

 former bring out the important fact that there is apparently no 

 internal boundary-line between the proglottids ; for the eggs form 

 continuous masses stretching without intermission from segment 

 to segment. In this region the most careful search failed to show 

 any other genital organs than these exceedingly numerous ripe 

 ova. It is, of coui^se, not uncommon in fully mature segments 

 of tapeworms, such as these in the present form, to find nothing 

 but ova in the medulla ; but in those forms there are at least 

 considerable though often altered remains of the genital ducts 

 and terminal apparatus. In the present species there is no 

 vestige of cirrus-sac or vagina and not the least trace that I 

 could discover of an external pore. Nor do I think that it would 

 have been easy to have missed these structures were they present, 

 particularly in a series of sagittal sections. I am, in fact, con- 

 vinced that they are absent. 



The eggs of this tapeworm do not lie in any space or spaces 

 that can be strictly called a uterus. There are, however, spaces 

 which suggest the remains of the uterus. These are not arranged 

 in strict metamerism ; but in a certain number of proglottids, 

 and not by any means confined to a single proglottid, are large 

 cavities such as is represented in the accompanying text-figure 

 (text-fig. 120). These cavities are more or less circular and lie 

 in the medullary region of the body. As a matter of fact, 

 they are not at all full of eggs. Indeed, they are often quite 

 empty ; only sometimes are eggs to be seen lying within them 



