67 



or more matured joints are the farthest from the head ; 

 and the cicatrized notch is always visible in the last 

 joint during the process of growth, until this latter is 

 cast off. Its absence, therefore, indicates that seg- 

 ments have been cast. The one bearing the notch, 

 however, is generally sterile (Kiichenmeister) ; but the 

 others are not thrown off until the joints are ripe and 

 fecundated. 



Before leaving this subject, it will be well to say a 

 few words about the embryo of the Bothriocephalus 

 (PL II. fig. 3, A). The scolex is not known ; neither 

 is the process of its development. The embryo is 

 ciliated, lives in the water, and is supposed to be 

 developed in certain kinds of fishes ; as, for instance, 

 the so-called Bothriocephalus solidus, which is found 

 in the abdominal cavity of the stickleback. This 

 fish is eaten by some larger fish or by some water- 

 fowl, and the scolex is then further developed into the 

 mature worm, e.g., the B. nodosus, which Von Siebold 

 states to be nothing but a further development of the 

 B. solidus of the stickleback. It is therefore proba- 

 ble, that the same condition of things obtains in others 

 of the Bothriocephali. 



We have now followed the embryo in all its wander- 

 ings, from its exit from the ovum, to its debut, as an 

 adult tapeworm. Interesting as it would be to discuss 

 some of the experiments performed by various observ- 

 ers in confirmation of the statements made with regard 

 to the development of the Tsenia? from the Cysticerci, 

 my time and space will not permit me to here do fur- 

 ther than to allude to them, by referring those inter- 



