222 ENTOZOA. 



second pliase, it becomes a non-sexual Cysticercus (these two 

 pliases together constituting the protozooid) ; in the third change 

 it gives off, by budding, numerous gemmules, most of them des- 

 tined to be sexually-mature individuals (or deuterozooids) , in 

 this way resembling their original parents.'* 



As I have already attempted to show in the case of Tcenia 

 serrata, the relation and nature of these developmental changes 

 may be farther simplified by placing the various life phases in a 

 tabulated form, as follows : — 



a. Egg in all stages. 



h. Six-hooked embryo = proscolex. 



c. Resting larva or Cysticercus (teles) C 

 Zoological Individual ■ ■ . ^ celluloses (scolex). J 



d. Immature tapeworm. 



e. StrobUa, or sexually-mature Tcenia solium, 

 f. Proglottis (cucurbitinus)= free segment^deuterozooid. 



Injurious effects upon Man. — The common tapeworm may be 

 said to act prejudicially against our species in three different 

 ways. It may directly cause disease and dea^ih by infesting our 

 bodies, at one time in the adult, and at another time in the larval 

 state ; it may also indirectly affect our health and wealth by ren- 

 dering the flesh of swine innutritions or altogether unfit to be used 

 as food. 



When one or more sexually-mature tapeworms have developed 

 themselves within the human intestine, they give rise to a variety 

 of unpleasant symptoms, more or less marked according to the 

 habit or irritability of the patient. According to Davaine (p. 103 

 of his " Traite") the principal features are "vertigo, noises in the 

 ears, impairment of sight, itching of the nose and anus, salivation, 

 dyspepsia and loss of appetite, colic, pains over the epigastrium and 

 in different parts of the abdomen, palpitation, syncope, the sensa- 

 tion of weight in the abdomen, pains and lassitude in the limbs, and 



* Part of the above is taken from my article, " Alternation of Generations," in the 

 supplement to the sixth edition of " Maunder's Natural History." 



