366 HENRY LESLIE OSBORN. 



EXPLANATION OF PLATE I. 



FIG. i. View of the inner aspect of the right half of the lower jaw of a specimen 

 of the small-mouthed black bass, from Ohio; showing the white cysts of C. mar- 

 ginatum at the bases of the branchiostegal rays, and black spots of an unidentified 

 nature. Natural size. 



FIG. 2. A cyst of C. marginatum in place among the muscle fibers of the bass 

 from Nebish, Mich., from a glycerine preparation after teasing off part of the mus- 

 cular tissue. 



FIG. 3. View of a section passing through a cyst in place in the muscle tissue 

 of the bass, from Nebish, Mich. Camera lucida, X24 diameters. 



FIG. 4. View from a section of a cyst in a plane transverse to the muscle tissue, 

 showing in detail the histological structure of the wall of the cyst; from bass from 

 Nebish, Mich. Camera lucida. X340 diameters. 



FIG. 5. Drawn from a specimen of C. marginatum, which had been removed 

 from the cyst after fixation in alcohol and relaxed by slight maceration; from bass 

 from Nebish, Mich. 



FIG. 6. Sketch of living animal in "suctorial pose" as seen from ventral side; 

 from bass, Nebish, Mich. 



FIG. 7. From a sagittal section of anterior end of worm which died in "suc- 

 torial pose," from heron, Nebish, Mich. Camera lucida, X 38 diameters. 



FIG. 8. View of ventral surface of a living animal in the "swimming pose," 

 from bass, Nebish, Mich. 



FIG. 9. View of a portion of the muscles of the ventral ccelomic wall of frog, 

 showing a cyst and enclosed worm. From specimen after clearing and mounting 

 in balsam. St. Paul, Minn. Camera lucida, X ^5 diameters. 



