6 University of Michigan 



boscides from an earlier acanthocephalan infestation. All of 

 the purely negative records for this species arc thus based 

 upon examinations of immature lish. 



Microptcrns dolumicn Lacepede. Small-mouthed Black Bass. 



Specimens examined: lo. Infested with Acanthocephala : lo. 



Analysis of Infestation 



No. of 

 Species represented in individual liost instances 



E. thecatus Linton, only 8 



P. bulbocolli Linkins 

 U. tliccatns 



M. dulomicu is preeminently the definitive host of B. the- 

 catus in the region under consideration. Every fish examined 

 contained this parasite in the digestive tract in numbers rang- 

 ing from a single specimen to more than a hundred. In one 

 host two individuals were removed from cysts, one from the 

 ovary and one from the liver. In both these instances the 

 parasites were small and immature. This would indicate that 

 their ])resence outside of the digestive tract resulted from 

 .adaptability of the bass to the role of intermediate host for this 

 species. This same species was frequently taken from the 

 •.stomach of the host though the intestine and pyloric caeca 

 seem to be the normal and more usual habitat. 



A single specimen of P. hnlhocolii was taken from the in- 

 testine of each of two hosts. Both of them were normal 

 mature individuals. 



Micropterns sahnoidcs (Lacepede). Large-mouthed Black Bass. 



Specimens examined: 4. Infested with Acanthocephala: 4. 



Bchinorhynchus thecatus is the only species of Acantho- 

 cephala discovered in the large-mouthed black bass of this local- 

 ity. It occurred in each of the four individuals examined, 

 though in much smaller numbers than encountered in M. 



