PL A TE XIII. 



EXPLANATION. 

 FIG. 



1-9. MONAS DALLINGERI, S. K. (after Dallinger and Drysdale). i, Normal adult 

 form, x 2000 ; 2, monad preparing to assume an encysted state ; 3, 4, 5, 

 progressive phases following upon encystment, and resulting in the produc- 

 tion of a spherular aggregation of elongate vermicular macrospores ; 6, the 

 same macrospores liberated as simple monads resembling the parent, but of 

 smaller size ; 7, conjugation of larger and smaller monads j 8, encystment 

 resulting from such conjugation ; 9, the compound cyst bursting and 

 liberating infinitesimally minute microspores. 



10-18. MONAS FLUIDA, Duj. 10, Typical adult monad, x 1000 ; 11-16, metamorphic 

 forms of similar adult monads; 17, congregation of two zooids ; 18, their 

 encystment. 

 19. MONAS IRREGULARIS, Pty. (Cienkowski), x 350. 



20, 21. MONAS OBESA, Stein sp., x 650 (Stein). 



22-24. MONAS RAMULOSA, Stein sp. x 600 (Stein). 



25, 26. LEPTOMONAS BUTSCHLII, S. K. (Biitsch.). 25, A group attached by their 

 posterior extremities, x 600 ; 26, a free-swimming monad, x 1 500. 



27, 28. OPHIDOMONAS JENENSIS, Ehr., x 600 (Ehr.). 



29-34. HERPETOMONAS MUSCLE-DOM ESTICLE, Burnet sp. (Stein). 29-32, Polymorphic 

 phases of the adult monads, x 650 ; 33 and 34, monads dividing by longi- 

 tudinal fission. 



35-40. HERPETOMONAS LEWISII, S. K. (Lewis). 35-38, Various contours of the adult 

 organism, x 800 ; 39, two red and forty-one colourless corpuscles of the rat's 

 blood which they inhabited, equally magnified to show proportionate size. 



41, 42. SCYTOMONAS PUSILLA, St., X 650 (Stein). 



43, 44. PLEUROMONAS JACULANS, Pty., x 500 (Perty). 



45. MEROTRICHA BACILLATA, Meresch. (Dimensions unrecorded) (Mereschkowski). 



46, 47. CYATHOMONAS ELONGATA, From. 47, Dividing by longitudinal fission, 600 



(De Fromentel). 

 48. CYATHOMONAS TURBINATA, From., x 400 (De Fromentel). 



49-53. ANCYROMONAS SIGMOIDES, S. K. 49, Free-swimming animalcule, x 1500; 50, 

 animalcule fixed by distal termination of the single flagellum, the dotted 

 outline indicating the position alternately assumed by the body with relation 

 to the flagellum in the course of its rapid oscillations, x 2500 ; 51-53, showing 

 the several progressive phases of oblique fission. 



