964 DESCRIPTIOX OF THE EXGRAYIXGS. 



PLATE XL. (Rotatoria). 



Figure 1. Hvdatina senta, female, lateral view : a, dorsum and oral cavity, extending 

 to an apex at b ; c, mastax with maxilla^ ; d, canal between mastax and stomach ; /, cloacal 

 orifice ; g, vesicle ; h, ovary ; /, coils of respiratory tube ; k, cerebral ganglion ; /, cDiated 

 tactile fossa; m, longitudinal muscles. 2. Enteroplea Hydatina, the male of Hydatina 

 senta. 3. Ova in an immatiu-e state, as found in the unimpregnated ovary of Hydatina 

 senta : a. germinal spot ; b, germinal vesicle ; c, membrane of ovum occupied vnih gi-anular 

 yelk-matter. 4. The lining membrane of stomach of Hydatina senta, everted, sliowing 

 cilia. 5. Yibratile tag, supported on its pedicle, attached to the respiratory canal. 6. The 

 male sexual organs (of Enteroplea Hydatina) detached, and highly magnified : a, penis ; 

 b, gland surrounding its bag ; c, vesicles with granides ; d, fold of integument surrounding 

 penis when retracted. 7. Detached sjiermatozoa. 8. Stephanops muticus, seen from 

 ben ea til. 9. Same, side view. 10. Another view from beneath, or the ventral svu-face. 

 11. Brachionus Dorcas, female, newly born. 12. Same, male, newly born (Gosse). 

 13. B. Miilleri (male) : a, head mass ; b, eye ; c, muscles ; d, posterior mass ; e, sperm- 

 sac ; /, urinary concretion ; g, foot. 14. B. Pala, male, newly born. 15. Same, male 

 egg, nearly mature. 16. B. Bakeri. 17. Sacculus viridis, male, newly born. 18. Same, 

 female, with male ova attached. 19. Bracliionus angularis, male. 20. B. urceolaris, 

 mastax and dental apparatus, ventral aspect : a, mastax ; b, malleus ; c, manubrium ; 

 d, articulation ; e, uncus ; /. incus ; //, ramvis ; h, fulcrvmi ; /, muscle connecting the micus 

 with the ramus ; j, muscle for extending tl^p malleus ; /, muscle for thro^ning in the 

 manubrium ; k, muscle for bending the malleus ; m, buccal funnel ; n, salivary glands ; 

 0. alula. [These letters have the same signification where met with in the following figures 

 after Gosse:] 21-23. B. m-ceolaris : 21. Jaws viewed nearly from above; 22. Dental 

 apparatus, lateral aspect ; 23. Buccal funnel, salivary glands, mastax, and dental appa- 

 ratus, dorsal aspect. 24. Diglena forcipata, jaws closed, ventral aspect. 25. Floscularia 

 ornata. jaws, dorsal aspect. 26. The same, frontal aspect. 27. Stephanoceros Eicli- 

 hornii. jaws, dorsal aspect. 28. Same, uncus, oblique aspect. 



