614 ARTHUR E. SHIPLEY. 



end, the whole body is hollowed so that each segment is curved. 

 The most posterior segments, which are crowded with embryos 

 well advanced in their development, are rounder, less flat- 

 tened, longer, and they readily broke off. 



I was not able to detect any genital pore on the exterior 

 even with the aid of powerful lenses, but sections (figs. 4 and 

 6) and stained mounted specimens show that it is on the same 

 side of tlie body in all the segments. 



The head of the tapeworm bears four sucisers, and in the 

 midst of them is the rostellum (fig. 9). The shape of the 

 head is very various : in some cases the suckers are, as it were, 

 hunched up and lying at each corner of a square, the lateral 

 diameter of which does not exceed the dorso-ventral (fig. 8) ; 

 in other specimens the head is not separated from the body by 

 a deep constriction, but is flattened and spread out (fig. 7), so 

 that the lateral suckers are separated from one another by a 

 space considerably wider than that which lies between the dorsal 

 and the ventral suckers. 



The rostellum is minute and sunk in a pit (fig. 3); it bears 

 a wreath of ten hooks. In all the specimens which I cut into 

 sections, and I think in the others as well, the rostellum was 

 retracted, the points of the hooks folded in against the axis of 

 the rostellum, and not reaching so far forward as the mouth 

 of the pit. When the animal is fixed to the mucous mem- 

 brane of its host this rostellum is doubtless protruded from 

 its sheath, and the hooks are divaricated. Certain muscle- 

 fibres which run from the base of the rostellum, and lose them- 

 selves in the parenchyma, probably serve to retract it. 



The hooks are slightly curved, and the projection which 

 corresponds with the inner fork of the more triradiate hooks 

 of other genera is hardly, if at all, marked (fig. 3). Measur- 

 ing in a straight line from the base to the tip the hooks are 

 18 — 23 fx in length, thus corresponding pretty closely with 

 those of Drepanidotaenia teuuirostris, which, according 

 to Railliet,! measure 20 to 23 ju, and to those of D. lanceo- 

 lata, which measure 25 to 31 ju. 



1 ' Traite de Zoologie medicale et agricole,' Paris, 1895. 



