ON A NEW CESTODE LARVA PARASITIC IN MAN. 9 



during the process of removal from the capsule, however carefully 

 this was done. In oilier cases a slight pressure between glasses 

 sufficed to effect the separation at the constricted place. After 

 all I have observed, there can be no doubt that the worm has 

 the power of dividing and multiplying on its own account within 

 the capsule. Thus the worm shown in fig. 5 may be looked 

 upon in the light of one which is about to divide into two in 

 the middle. I return to this point again soon. 



Size and Shrtpe ; Biidding. — While many of the worms 

 are very small and filiform, measuring not over 0.3 mm. in breadth 

 and 3 mm. in length, others (such as those of figs. 4 and 5) 

 in a moderately contracted state are nearly 12 mm. long and 21mm. 

 broad. The latter, when fully extended, would probably double 

 in length but diminish considerably in breadth. 



To illustrate the various shapes presented by the worms I 

 have given in figs. 2-15 a selection of specimens, all killed with 

 sublimate solution while living and moving in a watch-glass. In 

 some specimens the body is distinctly flattened, without doubt in 

 the dorso-ventral direction (figs. 4 and 5). In other cases this 

 is not so apparent or is even scarcely perceptible ; but then the 

 body in transverse sections generally presents a more or less oval 

 outline (figs. 16 and 17). There exists no clue whatever to 

 decide which of the flattened sides is dorsal and which ventral. 



The shape of the worm in the simplest case is that of a 

 typical Plerocercoid (fig. 2 a-c ; figs. 3 and 13). It is simply 

 thread-like in the fully outstretched state or may consist, in a 

 moderately extended state, of the narrow, highly retractile head- 

 end and of the broader hind region, or when strongly contracted 

 may be of an irregularly cylindrical form, transversely folded on 



