PLATE XXI. 



EXPLANATION. 

 FIG. 



i. PHACUS TRIQUETER, Ehr. sp., vol. i. p. 387. a a, Amylaceous corpuscles; e, 

 eye-like pigment-spot, x 600 (Stein). 



2-5. PHACUS PLEURONECTES, Ehr. sp., vol. i. p. 386 (Stein). 2, Normal animalcule, 

 x 600 ; 3, example with the nucleus or endoplast divided into four frag- 

 ments, those at g g being further separated into germinal elements, consti- 

 tuting the so-called " germ-sacs " or " germ-spheres " of Professor Stein ; 4, 

 an instance of transverse fission ; 5, indurated membrane or carapace left 

 after the decay of the enclosed body-substance. 



6, 7. PHACUS LONGICAUDUS, Ehr. sp., vol. i. p. 387 (Stein). 6, More normal form ; 

 7, spirally twisted non-flagellate example, x 300. 



8,9. CHLOROPELTIS HISPIDULA, Eichwald, vol. i. p. 388. 8, Lateral, 9, ventral 

 aspect, x 600 (Stein). 



10. PHACUS PYRUM, Ehr. sp., vol. i. p. 387, x 600 (Stein). 



1 1-13. CHLOROPELTIS OVUM, Ehr., vol. i. p. 388. a a, Amylaceous corpuscles ; 13, 

 subcylindrical variety, x 600 (Stein). 



14-16. TRACHELOMONAS VOLVOCINA, Ehr., vol. i. p. 389 (Stein). 14, Normal type, 

 x 500; 15, animalcule with flagellum retracted, emerging from its lorica; 

 1 6, example bursting and liberating monadiform germs. 



17. TRACHELOMONAS RUGULOSA, St., vol. i. p. 389, x 500 (Stein). 



18, 19. TRACHELOMONAS LAGENELLA, Ehr. sp., vol. i. p. 389 (Stein). 19, Encysted 

 example with body divided by transverse fission, x 500. 



20. TRACHELOMONAS CYLINDRICA, Ehr., vol. i. p. 390, x 600 (Stein). 



21-23. TRACHELOMONAS HISPIDA, Pty. sp., vol. i. p. 390 (Stein). 21, Necked variety, 

 X 500 ; 22, neckless variety, with animalcule emerging from its lorica ; 23, 

 example with lorica invested with an outer mucilaginous covering. 



24. TRACHELOMONAS CAUDATA, Ehr. sp., vol. i. p. 391, x 500 (Stein). 



25. TRACHELOMONAS ARMATA, Ehr. sp., vol. i. p. 390, x 500 (Stein). 



26. TRACHELOMONAS ACUMINATA, Schmarda, vol. i. p. 391, x 450 (Stein). 



27. TRACHELOMONAS EURYSTOMA, St., vol. i. p. 390, x 500 (Stein). 



28, 29. ASCOGLENA VAGINICOLA, St., vol. i. p. 393 (Stein). 28, Normal form, x 500 ; 

 29, example divided by transverse fission, the anterior segment emerging 

 from the parent lorica. 



