-a 

 o 

 PQ 



AMOZBA. 



Shell composed of sand-grains or other PAO R. 



material, mouth terminal or subter- 



minal, Difflugia, 10 



Shell compressed ovoid to pyriform, 



transparent, chitinoid, Hyalosphenia, 16 



Shell compressed pyriform, of thin, square 



chitinoid plates, Quadrula, 19 



Shell compressed pyriform, colorless, of 



oval or circular or angular disks, with 



incorporated extrinsic elements, mouth 



oval, Nebela, 20 



Shell chitinoid, reticulated, often with 



sand-grains at the fundus, Heleopera, 24 



Shell chitinoid, hexagonal cancellated, 



usually bell-shaped ; base concavely 



infundibuliform, Arcella, 25 



Shell discoid, mouth eccentric, with or 



without spines, never cancellated, Centropyxis, 28 



Shell flexible, chitinoid, sarcode in- 

 timately adherent, Cochltopodium, 29 



DESCRIPTION OF GENERA AND SPECIES. 



GENUS I. AMCEBA. 



When at rest, a spherical or oval mass of soft, hyaline, 

 colorless, granular protoplasm. When in motion, form 

 variable. Ectosarc hyaline and minutely granular. En- 

 dosarc continuous with the former, finely and coarsely 

 granular, with corpuscles of varied character, ingesta of 

 food, etc. Nuclei and one or more pulsating vacuoles. 

 Pseudopodia digitate, simple or branched. 



Amoeba proteus. In globular form, diameter 200^ 

 in ovoidal form, 300// by 150//, extended in a dendroid 

 form, 500// in length by 400/* in breadth. This is one 

 of the largest species. It is nearly colorless or more or 



