20 ENTOZOA FOUND IN MAN. 



eye. It has been observed in man, and in several 

 mammiferse. 



Section B. Taeniae in the Perfect State. (Ribbon- 

 shaped form, or Free Proglottis). 



The taeniae, when in the perfect state, present 

 themselves in two conditions. 



1. In one the proglottis, shortly after being 

 formed, leaves the scolex or the strobile before it 

 becomes completely adult ; it hves free in the intes- 

 tine, moves about, is nourished, increases and attains 

 its perfect development as well as that which remains 

 indefinitely adherent. 



2. In another condition, which is perhaps the 

 more common, the Proglottides, continuous with each 

 other and with the Scolex, form a chain of varying 

 length (the Strobile). In this situation the Proglot- 

 tides attain their complete development ; those which 

 are nearest to the scolex do not present any trace of 

 reproductive organs, until the more distant ones, 

 which are completely adult, present perfectly deve- 

 loped ovules ; the male organ disappears first, and at 

 a later period the female organ, in consequence of 

 the I'upture of the walls of the ovary, and sometimes, 

 indeed, the proglottis, whose existence is terminated, 

 still adheres to the common chain. 



The ripe ovules always enclose a six-hooked 

 embryo. They exist in a prodigious number : 

 Dujardin has calculated that in a taenia serrata,^ a 

 cestoid worm, which does not acquire a very great 

 length, there were 25,000„000 eggs. The ovules 

 possess great tenacity of life, and can remain for a 



' Very common in tlie small intestines of the dog. 



