654 MR. F. E. BEDDARD ON 



The cirrus of each segment is not visible, or at least not con- 

 spicuous, when the worm is viewed with a lens, in a protruded 

 condition. This is due to the small size of these organs, which 

 will be more fully described later. I have not found it possible 

 to difierentiate the venti-al from the dorsal surface. The scolex, as 

 already stated, is unarmed. I investigated this part of the worm 

 by the section method, and am therefore able to state positively 

 that there is no rostellum nor any trace of hooks. Nor do the 

 suckers show any hooks that I could detect. I am convinced 

 that they are absent altogether from the scolex of this worm. A 

 regular series of transverse sections across the " head " shows a 

 rostellar region above the region of the suckers, which is oblong 

 in section ; it contains no pit or depression of any kind that was 

 obvious to me. The suckers are the usual four and as usual 

 symmetrical. When the scolex is viewed in its entirety under a 

 low power of the microscope the suckers seem to face rather 

 upwards ; but they do not lie on the upper side of the head as in 

 some Tetracotylea. There is only a slight obliquity. The orifice 

 of the sucker in such a preparation is very plain and rounded. 

 There is no appearance of a slit-like orifice such as is described 

 in the present paper in Oocliorkticu, and certain details in the 

 minute structure of the suckei's in these two genera show corre- 

 sponding diflerences. I find in two series of tiansverse 

 sections of the suckers of the two Tapeworms, that in the present 

 species eleven or twelve sections displayed the entire sucker, 

 of which only five showed its cup-like orifice; in Oochoristica, 

 on the other hand, the entire sucker required seventeen sections 

 of equal thickness for its display, of which twelve or thirteen 

 showed the ob\'iously more slit-like orifice. 



As in Oochoristica the orifice of the external integument is 

 much more limited than that of the sucker itself. The two coin- 

 cided for only the space of two sections, rather less than in 

 Oochoristica. This, however, I take to be simply a measure of the 

 state of contraction of the suckers. It is also important to notice 

 that the outer integument is grooved for a little space anteriorly 

 to the appearance of the sucker itself, which suggests a con- 

 firmation of a view already put forward, and that is the inde- 

 pendence of the suckei-s of the more specialised Tapeworms from 

 the bothria of the Dibothriata. It appears to be possible that 

 this grooving is the persistent trace of the bothrium, upon which 

 the sucker has been added as a subsequent development. 



In series of transverse sections through the head there is 

 another feature of the suckers which deserves mention. It is 

 very clear from such sections that the growth of the suckei- 

 has taken place in a definite direction. 



Although I am unable to give histological details, it is certainly 

 the fact that anteriorly the sucker is in organic connection with 

 the general tissues of the head. There is no break ; it begins 

 gradually with a recognisable condensation of tissue marked by 

 its deeper staining with carraine. On the other hand, at the 



