468 PARASITES OF ANTMALS 



invasion of tapeworms are the sturgeons, blennies, gobios, 

 mullets, sparoids, and Sciaense. Some few of them are infested 

 by Ligula, Caryophyll&i, &c. Cuttle fishes harbor a great 

 variety of tapeworm-larvae, forming one of the chief sources 

 whence sharks and rays obtain the same parasites destined to 

 arrive at sexual maturity within their own bodies. 



Among the most interesting cestodes of fishes we may reckon 

 the pit-headed tapeworms and their allies (Bothriocephalidae). 

 One of the most common species is Both, proboscideus which 





FIG. 80. Section of the strobile of Botkriocephatiu proloscideus. Magnified. After Busk. 



is found, often in considerable numbers, lodged within 

 the pyloric appendages of the salmon (Salmo salar and 8. 

 hucho). It acquires a length of two feet. When in large 

 numbers it cannot fail to prove injurious to the bearer. In this 

 connection also must be mentioned B. nodosus. In the adult 

 state this worm infests a great variety of water-birds (herons, 



