PLATE X. 



The lettering is the same in all the figures. 



Ophiodiscus annulatxis (figs. 1-10). 



Fig. 1. A portion of the animal, seen from the side ; magnified a little. 



Fig. 2. Transverse section through a tentacle near the base. Unscr. A, Oc. 2. 



Fig. 3. A portion of the animal seen from the oral side ; natural size. 



Fig. 4. A principal septum with the two adj oining genital septa ; magnified a little. 



Fig. 5. Transverse section through the oral disk at the insertion of a septum. A, 

 Oc. 2. 



Fig. 6. Transverse sections through difi"ereut parts of the circular muscle : a througli 

 the upper part, S through the lower end. Unscr. A, Oc. 2. 



Fig. 7. Portions of the circular muscle, more highly magnified ; a from the upper, /3 

 from the lower end. D, Oc. 2. 



Fig. 8. Pseudo-tentacle, slightly magnified. 



Fig. 9. Some terminal branches of the pseudo-tentacle, ten times the natural size. 



Fig. 10. Longitudinal section through a branch of the pseudo-tentacle. J, Oc. I ; 

 and reduced one half. 



Antholoha reticulata (figs. 11 and 12). 



Fig. 11. Transverse section through the circular muscle. D, Oc. 2. 

 Fig. 12. Transverse section through the oral di.sk. C, Oc. 1. 



