Maskell. — On Freshwater Infusoria. 19 



EXPLANATION OF PLATES I.-IV. 

 Plate I. 

 Fig. 1. Monas claviculus x 700; a, extended; b, contracted form. 

 Fig. 2. Dendromonas producta ; a, complete zoodendrium X 700 ; b, three 

 animalcules and pedicles X 1000. 

 Cephalothanmium coronatum X 700. 

 Goniomonas elongata X 700, in various positions. 

 Salpingsca inquillata, X 1000. 

 Salpingffica steinii, var. (?) X 1000. 

 Trachelomonas teres, X 600. 

 Anisonema ovatum, X 800. / 



Gymnodinium varians, X 700. 

 Nassula ambigua, var. tumida, X 300. 

 Fig. 11. Chcenia crassa ; a, extended animalcule X 100 ; b, oral aperture 



and canal, during inglutition of Urocentrum turbo, X 400. 

 Fig. 12. Amphileptus irregularis, X 350. 



Plate II. 



Fig. 13. Amphileptus rotundus, X 350. 



Fig. 14. Amphileptus tracheloides, X 200, in different positions. 



Fig. 15. Stentor attenuatus X 60 ; a, extended animalcules ; b, c, free- 

 swimming forms ; at d, vibratile fringe denoting commence- 

 ment of propagation by fission. 



Plate III. 



Fig. 16. Tintinnidium fluviatile, var. emarginatum ; a, animalcules in 

 tubes X 350 ; /;, animalcule X 700 ; c, free-swimming form 

 X 350 ; d, end-view, free-swimming, X 700. 



Fig. 17. Strombidium intermedium, X 700 ; a, normal animalcule ; b, 

 end-view of the same ; c, propagation by fission, the new zooid 

 at right angles to the old. 



Fig. 18. Mesodinium phialinum, X 700; a, side-view; b, end-view. 



Fig. 19. Zoothamnium limpidum ; a, zoodendrium X 200 ; b, portion of 

 stem and branches, showing the continuous muscular fibre, 

 X 700. 



Fig. 20. Cothurnia parallela, X 200. 



Fig. 21. Cothurnia amphorella, X 350. 



Fig. 22. Platycola decumbens, var. intermedia, X 200. 



Fig. 23. Phascolodon elongatus, X 350. 



Plate IV. 



Fig. 24. iEgyria astyla, X 350. 



Fig. 25. ^Egyria distyla, X 350. 



Fig. 26. Thurophora lucens ; a, animalcule, ventral aspect, X 350 ; b, oral 

 region and membranous valve, X 700 ; c, side-view of animal- 

 cule, X 350 ; d, section, in end-view, X 350. 



Fig. 27. Opisthotricha parallela, var. minor, X 350, dorsal aspect. 



Fig. 28. Acineta flos, X 700. 



Fig. 29. Acineta angularis, X 350. 



Fig. 30. Acineta tulipa, x 350. 



Fig. 31. Acineta lasanicola, X 350. 



