DESCETPTION OF THE ENGRAVLiSrGS. 959 



thydium Podura. 357, 358. Chcetonotus Larus. 359, 360. Glenophora Trochus. 

 361-364. CEcistes crystallinus. 365-370. Couochilus Volvos. 



PLATE XXVI. (PiiYTOzoA). 



The following figures are derived from M. Dujardin's excellent treatise, ' Histoire des 

 Infusoires' :— Figure 1. Hexamita nodulosa. 2. Authophysa Miilleri. 3,4. Acineta 

 tuberosa ; in 4 the cilia included. 5. Heteromita ovata. 6. Crumenula texta. 7. Poly- 

 selmis viridis. 8. Anisonema sulcata. 9 a, h. Oxyrrhis marina. 10 a, b. Ploeotia vitrea. 

 11. Heteronema marina. 12 a, b. Zyzoselmis nebulosa. 13. Peranema globulosa. 14. 

 Cyclidium distortum. 15. C. abscissum. 16 a, b. Acomia Cyclidium ; b, self-dividing. 



PLATE XXVII. (Protozoa). 



Figures 1-9. Vorticella microstoma : 1. With a bud growing from its base ; 2. A 

 specimen about to detach itself from its stalk, ai^.d having a posterior wTeath of cilia ; 3. Self- 

 division proceeding ; in 4 complete ; ba,b, c, d. Encysting-process ; 5 f . A cyst ruptured by 

 pressure, giving exit to the included Vorticella, apparently unchanged ; 6. Supposed transi- 

 tional forms from rudimentary campanulate organisms to undoubted Vorticella ; 7-9. 

 Process of encysting, and progressive disappearance of special organs. 10-15. Vaginicola 

 crystallina : 10. Self-division ; 11. One of the fission-products contracted and ready to 

 escape by means of its posterior wreath ; 12-15. Acinette formed from Vaginicolse. 16-23. 

 Epistylis nutans : 16. Two individuals on a stem ; the ciliary apparatus protruded in one, 

 contracted in the other ; 17, 18. Supposed Acinetce ; Acineta-body of the Epistylis ; in 17 

 the wavy outline indicates the contractions taking place in the integument ; in 18 the out- 

 stretched ciliary fibres or processes, two nuclei, and a large contractile vesicle are visible ; 

 19. Another such body, with its sm'face much contracted, and its contained substance 

 wasted by the development of embryonic nuclei ; 20. Another figure assumed by the 

 Acineta-body ; 21. The ultimately withered state arrived at by the Acineta-body of an 

 Epistylis, after the exhaustion of its contained formative blastema by the repeated produc- 

 tion of embryos ; 22, 23. Very young forms (probably) of the EpistyKs nutans, and appa- 

 rently the Epistylis Botrytis of Ehrenberg. 



PLATE XXVIIL (Protozoa). 



Figtires 1-3. Nassula ambigua : 1. Under surface ; the two long articulated filaments 

 within are portions of Oscillatoriee; c, vesicle; d, nucleus; 2. Encysted specimen ; 3. Ani- 

 malcule forced from its cyst by pressure. 4-7. Glaucoma scintillans : 4. Under sm'face ; 

 5. An encysted being, seen in 6 undergoing transverse fission, which in 7 appears oblique, 

 owing to a change of position of the resulting segments. 8, 9. Prorodon teres : 9. Its nucleus 

 surmoimted by a rim-like nucleolus. 10. Stylonychia Mytilus. (1-10, Stein.) 11-15. 

 Nassula elegans : in 11 internal germs occur in a cavity (uterine) communicating externally 

 by a canal (oviduct) ; 12. Germ loosing itself from the parent ; 13. A fission-product 

 ■enclosing a germ ; 14. Germ developing Acinetiform tentacles ; 15. Nucleus terminated 

 at its narrow end by a nucleolus. 16. Stentor Miilleri, surrounded by an envelope with 

 monads in its interior; 17. Same, animal contracted in its case. (11-17, Cohn). 18, 19. 

 Vaginicola valvata. The valve is seen closed at b in fig. 18 ; fission has occurred both in 

 this and in 19, but the animal is contracted in the former, and expanded in the latter 

 example; in 19 the valve appears as a streak parallel with one side. 20-23. Lagotia 

 viridis : 20. Head of a young individual ; 21. Lateral view of animal and of its ciliated 

 head ; 22. Tip of one of the lobes of ciliated head ; 23. Animal with front \-iew of head. 

 (18-23, Wright.) 24-26. Otostoma : the oral <3avity is seen as an ear-shaped space ; in 25 

 two vesicles also are seen opening externally. (Carter.) 27-30. Coenomorpha Medusula. 

 31. Panophrys griseola. 32. Habi'odon ciuwatus. 33, 34. Blepharisma hyalina. 35. 

 Cinetochilum margaritaceum. 36, 37. Cyclogramma rubens. 38, 39. Stichotricha 

 secunda. 40-42. Ptyxidium ovulum ; in 42. Act of fission. 43, 44. Stichotricha 

 secunda. 45. Colobidium pellucidimi. 46,47. Mitophora dubia. 48,49. Apionidium 

 modestimi. 50, 51. Lembadion bulliniun. 52-54. Baonidiimi remigans. 55-57. 

 Opisthiotricha tenuis. 58-60. Megatricha partita. 61. Acropisthium mutabile. 62, 63. 

 Siagontherium tenue. (27-63, Perty.) 64 a-k. Enchelys Farcimen, illustrating change of 

 form consequent on the introduction of food. 65-71. Nassula viridis : 65. Natm'al form, 

 X370; 66, 67. Cysts; 70, 69, 68, 71. Development of cyst-contents into monadiform 

 germs, enclosed within saccular thectc, and at length discharged externally as in fig. 71 : 



