1014 MR. F. E. BEDDARD ON 



the cortex. In correlation with their large numbers, the testes 

 are of small size. They cannot, obviously, be said to be either 

 dorsal or ventral or anterior or posterior in position. 



A good deal of the anterior part of each mature proglottid is 

 occupied by a large coil of the vas deferens which forms a larger 

 mass than in many tapeworms figured or known to me at first 

 hand. Although this coil lies anteriorly in the segment on a 

 level with the large cirrus sac, it does not touch the anterior 

 boundary of the segment. In front of it there is to be seen a 

 considerable heap of testes. The coil is generally in close contact 

 with the cirrus sac. I found no vesicvila seminalis in this species, 

 but the coiled tabe gets wider when ripe. 



The cirrus sac and its contained structures are rather re- 

 markable in this species and much moie complicated than in 

 many other species, including the three that I have already 

 described in my former communication *. As already stated, 

 the organs of reproduction appear very early in the chain of 

 proglottids. It is, however, not for some segments that the 

 cirrus sac is fully developed. The fully developed cirrus sac 

 coincides with the first appearance of the uterus. As already 

 mentioned, in considering the external characters of this worm, 

 the cirrus sac when mature is so large as to cause an appreciable 

 bulge in the segment. It therefore entirely fills the medullary 

 region of that part of the segment Avhere it occurs, as seen in 

 a transverse section. In svich sections it may also be seen 

 that the cirrus sac and the genital cloaca together (of which 

 a description follows) occupy about one-third of the entire breadth 

 of a proglottid. 



The cirrus sac is nearly if not quite spherical in shape, and 

 consists of an outer coat and of an inner mass of tissue. The 

 outer coat is not very thick and is muscular, the fibres no doubt 

 serving to compress the sac and thus bring about the evagi- 

 nation of the cirrus. The internal tissue of the cirrus sac is 

 a tissue in which the cirrus itself is embedded, and it entirely 

 fills the sac save where it is traversed by the cirrus. It contains 

 many nuclei scattered fairly closely throughout it, and delicate 

 fibres which may be occasionally seen to possess a distinctly 

 retiform arrangement. It seems to me to be a soft tissue which 

 is an elastic packing material transmitting to the cirrus the 

 contractions of the external muscular coat of the cirrus sac. In 

 some sections indeed the nuclei can be seen to be more compressed 

 and regularly arranged in lines in the immediate neighbourhood 

 of the eversible cirrus sac. This might seem to argue some 

 contractility possessed by the tissue forming the core of the 

 cirrus sac. 



The cirrus itself is peculiar and complicated in structure. It 

 consists of two parts. First of all there is the part which lies 

 immediately within the cirrus sac and which is perfectly con- 

 tinuous with the vas defei-ens, and shows no sudden differences 



* P. Z. S. 1911, p. 626. 



