PLATE III. 



The following letters have the same signification throughout. 



cl. Cloacal papilla. 

 p. Parapodium. 

 ph. Pharynx. 



s. Sucker. 

 (5 . Male genital papilla 



Figs. 1-4. Myzostoma heardi, n. sp. 



Figs. 1-3. Three aspects of the arm swelling, a, the hypozygal of the syzygy. 

 Fig. 4 The Myzostoma, seen from the ventral side ; magnified 38 diameters. 



Figs. 5, 6. Myzostoma willemoesii, Graff. 



Fig. 5. The deformed pinnule, with the enlarged ambulacral furrow (*) and its free 



(not deformed) end (a); magnified 5^ diameters. 



Fig. 6. The left margin of the body with (III-VII) cirri. 



Figs. 7-12. Myzostoma platypus, n. sp. 



Figs. 7, 8. Two views of the cyst, a, the Myzostoma visible at the opening of the 

 cyst ; magnified 5^ diameters. 



Figs. 9, 10. The Myzostoma, seen from the ventral side, with its median elevations (1-5) ; 

 magnified 5-g diameters. 



Figs. 11, 12. The same, seen from the anterior end, with the first pair of cirri (c) ; 

 magnified 5g diameters. 



