and other Indigenous Rhizopods. 453 



EXPLANATION OF PLATE X. 



Fig. \. Actinophrys Eichhomii, showing the complete vacuolation of the 

 " cortical " and " medullary " portions. A Macrobiotus and an 

 Astasia are seen imdergoiag digestive absorption within the body, 

 these organisms being enclosed within separate food-vacuoles. 

 At m a second Macrobiotus is in the act of being drawn into the 

 peripheral substance, and partially surrounded by the layer of 

 sarcode which especially constitutes its special vacuole: c r, 

 c r, contractile vesicles. 



Fig. 2. A portion of the same individual, more highly magnified, in order 

 to show more distinctly the vacuolation and polygonal character 

 of the protoplasmic matter in this species of J cfinop^ry*: n,n, 

 nuclei; m, the Macrobiotus now completely enveloped by the 

 layer of sarcode, and being slowly drawn into the endosarc ; /, r, 

 a food-vacuole, either after its contents have been altogether 

 absorbed or after the excrementitious matter has been extruded. 

 Both the above organisms are shown as focused down to a hori- 

 zontal plane. 



Fig. 3. Showing the villous appearance of the depression produced on the 

 completion of the systole of the contractile vesicle. 



Fig. 4. Actinophrys Sol, containing a large Pinnularia within a food- 

 vacuole : 0, 0, oily globides within the protoplasm of the latter. 

 This specimen, which was obtained from Hampstead also, is 

 figured with a view to show how impossible it would be to distin- 

 guish it from an Amaba when, as often happens, the pseudo- 

 podia are entirely retracted. The food-vacuole was here very 

 distinct. 



Fig. 5. Nucleated corpuscles of Amoeba villosa. 



Fig. 6. Sarcoblasts or granular corpuscles of the same. 



Fig. 7- Rhombohedral crystalloids of the same. 



Fig. 8. Detached gemmule of the same, after the pseudosegmentation of the 

 granular protoplasm of which it is composed ; p, its mamiUiform 

 process. 



Fig. 9. A young Amoeba villosa, supposed to be the advanced stage of the 

 gemmule, fig. 8 : a, its villous tuft ; c v, contractile vesicle ; n, 

 nucleus. 



Fig. 10. Minute viviparous forms of ^. villosa. 



Fig. 11. Amoeba princeps (var. radiosa), showing an abortive effort at 

 fission : c v, contractile vesicle ; n, nucleus. 



Fig. 12. Difflugia proteiformis (var. septifera), showing a dithalamous ten- 

 denc}-. 



Fig. 13. Bifflugia proteiformis (var. acuminata), showing transitionary ten- 

 dency towards the characters of Arcella aculeata ; at c, the por- 

 tion of the test around the aperture built up entirely of chitinous 

 pellets, d, terminal spine. 



F^. 14. Showing the configuration of the test in Arcella vulgaris, consisting 

 of hexagonal depressions, through which the line of fracture ge- 

 nerally passes. 



Fig. 15. Showing the configuration of the test ofEuglypha ? from 



Stony Stratford ; the chitinous pellets taking a perfectly symme- 

 trical form, namely, discoidal masses connected one with the other 

 by regularly disposed bands of the same material. The line of 

 fracture accordingly follows that of the thinnest portion of the 

 test — that is to say, the spaces intervening between the rows of 

 pellets. 



