26 ENTOZOA FOUND IN MAN. 



In accordance with the idea entertained by some 

 helminthologists, that echinococci introduced into 

 the human intestines may be developed into taeniae, 

 Kiichenmeister suggests that the T. nana observed 

 by Bilharz had a similar origin. The cases collected 

 by Dr. Davaine appear, however, to point to a dif- 

 ferent conclusion ; out of thirty-six cases of hydatid 

 tumours evacuated through the intestinal canal, not 

 a single instance was noted in which taeniae made 

 their appearance ; in six of these an autopsy was 

 performed, and no cestoid worm of any species was 

 found in the intestines. To these cases might also 

 be added those of hydatid tumours in communication 

 with the bronchi, for in many of these cases the 

 evacuation of the echinococci through the mouth 

 occupied several months, and it is impossible that 

 the patient could have avoided swallowing them in 

 considerable quantity, both with the saliva and with 

 the food ; yet in thirty-two such cases, collected by 

 Dr. Davaine, not a single patient presented any 

 signs of taeniae, although a post-mortem examination 

 was made in twelve of them. 



Sub-Class II. — Bothriocephali. 



These are cestoid worms, possessing a head or 

 scolex, and rings furnished with male and female 

 reproductive organs, the orifices of which open at 

 the mid-line of one of the surfaces of each ring. 



The Embryonic and the Larval conditions of 

 these worms as are yet uncertain. 



