MORPHOLOGY OF OTOCYSTS OF GONIONEMUS. 



289 



with those of G. vcrtcns upon which the greater part of the work 

 was done. Specimens of G. vertens collected at Friday Harbor, 

 Washington, were submitted to Dr. Alfred G. Mayer and to Dr. 



TEXT FIGURE i. General organization of the otocyst of Gonionemus: pv, 

 primary vesicle; c, fluid filled cavity; s, spheroid; pp, primary pedicel; si>, 



secondary vesicle; o, otolith ; s p, secondary pedicel. 



/ 



Henry B. Bigelow, both of whom very kindly verified the tenta- 

 tive identification of the species. 



While the present paper deals primarily with the finer struc- 

 ture of the otocyst the latter part is devoted to a discussion of 

 the orientation of the otocyst in the organism. 



METHODS OF STUDY. 



Specimens preserved in formalin were too opaque for accurate 

 observations of the otocysts. Serial sections and toto-mounts 

 of the bell margin, including ring canal, otocysts, and tentacles 

 were prepared for the detailed study of the morphology and the 

 orientation of the otocysts. The toto-mounts were made by 



