A CESTODE PAKASITE IN THE FLESH OF THE BUTTERFISH. 131 



that the embryos have entered the circulation by way of the intestino-portal vessels 

 and have been carried to the heart , thence through the capillaries of t lie gills, and have, 

 for the most part, reached their final resting place by way of the dorsal aorta and 

 its continuation in the caudal aorta. As the blood current is checked in the small 

 arterial branches and capillaries the embryos make their way into the adjacent 

 muscular and connective tissue. 



3. Susceptibility of the butterfish to the encystment of 0. crenacolle in the 

 flesh, and immunity of other fish from the same. 



It is possible that a comparative study of the circulation and the splanchnic 

 anatomy of the butterfish and one of the species of fish in which cysts were found 

 in large numbers on and in the abdominal viscera may yield data for the solution 

 of this problem. 



