EXPLANATION OF PLATE XIX. 



FIG. 



1-14. TREPOMONAS AGILIS, Duj., vol. i. p. 300. 1-8, Animalcule from various points 

 of view, and with the body straight or twisted upon itself, as represented by 

 Stein, at 7 an example dividing by longitudinal fission, x 650 ; 9, character- 

 istic aspect as given by Perty; 10-12, other phases, as delineated by O. F. 

 Biitschli, the arrows in the last instance indicating the course followed by 

 the circulatory motion of the endoplasm ; 13 and 14, young animalcules 

 after Stein. 



15. CHLORASTER AGILIS, S. K., vol. i. p. 317, x 1250. 



16-19. CALLODICTYON TRICILIATUM, Carter, vol. i. p. 307. 17, an animalcule en- 

 veloping a vegetable filament, x 400 (Carter). 



20. CHLORASTER TETRARHYNCHUS, Schm., vol. i. p. 316, x 350 (Stein). 

 21, 22. CHLORASTER GYRANS, Ehr., vol. i. p. 316, x 250 (Stein). 



23-25. TRIMASTIX MARINA, S. K., vol. i. p. 312. 23 and 24, lateral, 25, oblique view, 

 x 1250. 



26, 27. TETRAMITUS SULCATUS, St., vol. i. p. 314, x 430 (Stein). 



28, 29. TETRASELMIS CORDIFORMIS, Carter sp., vol. i. p. 315, x 450 (Stein). 



30-32. TRICHOMONAS BATRACHORUM, Pty., vol. i. p. 308, x 650 (Stein). 



33, 34. TRICHOMONAS VAGINALIS, Duj., vol. i. p. 309, x 1000 (Dujardin). 



35-41. DALLINGERIA DRYSDALI, S. K., vol. i. p. 310 (Dallinger and Drysdale) ; 35, 

 animalcule fixed by two posterior flagella, and showing at a and b respective 

 positions occupied by the body during the alternate extensions and spiral 

 contractions of these appendages, x 2000 ; 36, free-swimming animalcule, 

 seen from above ; 37, example dividing by longitudinal fission ; 38, 

 animalcule with posterior flagella retracted and about to enter upon an 

 encysted state ; 39, encystment ; 40, sporocyst bursting and liberating clouds 

 of microspores, x 2000 ; 41, triflagellate monads developed from the liberated 

 microspores. 



42-48. TETRAMITUS ROSTRATUS, Pty., vol. i. p. 313 (43, 47, and 48 after Stein, the 

 remainder after Dallinger and Drysdale). 42, Normal free-swimming 

 animalcule, x 1000 ; 43, ventral view, showing groove-like channel ; 44 and 

 45, successive phases of longitudinal fission, accompanied by the assumption 

 of an irregular amcebiform contour ; 46, biflagellate animalcule derived by 

 fission with flagella in process of further subdivision, so as to reproduce the 

 normal number ; 47 and 48, young animalcules, X 650. 



49, 50. TETRAMITUS DESCISSUS, Pty., vol. i. p. 314, x 1500 (Biitschli). 

 51. LOPHOMONAS STRIATA, Biitschli, vol. i. p. 322, x 800 (Biitschli). 



52-54. LOPHOMONAS BLATTARUM, St., vol. i. p. 321. 52 after Biitschli, 53 and 54, 

 after Stein, x 650. 



55. HEXAMITA ROSTRATA, St., vol i. p. 320, x 650. 



56-59. HEXAMITA INFLATA, Duj., vol. i. p. 319 (56-58 after Stein). 56, normal adult 

 animalcule, x 650 ; 57, animalcule about to divide by longitudinal fission ; 

 58, example with posterior flagella entangled in floccose matter ; 59, animal- 

 cule fixed by the extremities of its posterior flagella, and gyrating upon the 

 same, as observed by the author, x 1000. 



60-62. HEXAMITA INTESTINALIS, Duj., vol. i. p. 318. 60, free- swimming animalcule, 

 x loco ; 61, example anchored by the posterior flagella, and actively vibrating 

 the four anterior ones ; 62, an example with toothed antero-lateral borders 

 and pseudopodic posterior prolongations (Stein). 



