T. B. ROSSETEK ON CYSTICEKCUS VENUSTA. 811 



round, forming a deep concavity under the anterior root ; which' 

 jutting out, forms a prominent, attenuated, anterior root 6. 

 Still following the face of the hook b-c, the back of the anterior 

 root curves inwards rather sharply, with a deep curve, then 

 bulges out — convex — at the posterior root c, which is blunt, as 

 if sharply cut off ; the back of the hook from c-a forms a 

 beautiful continuous bow. A thin line runs from b-c which 

 leaves a wide semi-opaque space. The hook of T. fragilis 

 thickens immediately it leaves the point a, and thus the curve 

 from a-b is shallow, more especially at the face of the anterior 

 root 6, which is blunt, or bossed; and, although it, like Fasciata 

 curves inwards, yet the curvature is shallow, and becomes con- 

 vex towards the posterior root, it then curves to form a minia- 

 ture hook of the posterior root c. A thin line also runs from 

 b-c as in Fasciata, but the semi opaque space is very limited. 



These, then, are the characteristic features of the hooks of 

 these two Taeniae, whose measurement approaches so nearly to 

 that of the new Taeniae. I will now contrast them with the 

 hooks of this latter. 



In the first place the hooks measure O051 mm. ; in some 

 instances in the Cysticercoid stage they are a little in excess 

 of this measurement, thus they are 0'005 mm. less in length 

 than either Fasciata or Fragilis. Again, the division of the 

 hook from a-b is 0010 mm. less in either case, whilst b-c is 

 0004 mm. longer ; in other words, the hook is shorter, and the 

 posterior root or shank longer than either T. fasciata or T. fra- 

 gilis. The formation of the hook, moreover, is different to those 

 in the latter two species, for it is somewhat obtusely pointed at a 

 and slightly curves inwards to form the anterior root 6, which 

 is stout, or bossed somewhat similar to the anterior root of T. 

 liophallus. — In a few instances it runs downwards in a straight 

 line for about 0'007 mm., then, instead of curving, it follows a 

 course almost parallel with the back of the hook, until it 

 arrives at the posterior root c, where it abruptly makes a short 

 right angle, then circles round with a smooth surface to meet 

 the back of the posterior root, which pursues a straight course 

 past the anterior root, where it becomes convex to form the 

 claw. The width of the hook at the anterior root is 0010 

 mm. ; and there is no semi-opaque space from b-c. In some 

 cases the posterior root b-c is tuberculated (Fig. 5). 



