40 BRITISH PBESHWATEB EHIZOPODA. 



occasionally digitate, and, in the resting phase of the 

 organism, persistent. 4. Pelomyxa. 



Body discoid, pseudopodia lobose (hernia-like) ; 

 endoplasm containing numerous minute reniform con- 

 cretions; nucleus large, punctate. 5. Lithamceba. 



Amoeboid; the plasma-body furnished at the pos- 

 terior extremity with numerous straight, usually arti- 

 culate, protoplasmic filaments. 6. Ouramosba. 



Genus 1. AMOEBA Ehrenberg, 1832. 



Volvox, (pars) LINN^IUS Syst. Nat. ed. 10, I (1758), p. 820. 

 Chaos (pars) LINNAEUS Syst. Nat. ed. 12, I, pt. 2 (1767), p. 



1326. 

 Vibrio (pars) O. F. MULLER Verm. Terr, et Fluv. I (1773), 



p. 45. 

 Proteus (pars) 0. F. MULLER Aiiimalc. Infus. (1786), p. 9. 



Non Proteus BAKER Empl. Micr. (1753), p. 260. 

 Amlba (pars) BOEY DE ST. VINCENT in Diet, class. Hist. Nat. 



I (1822), p. 261. 

 Amoeba (pars) EHRENBERG in Abh. K. Akad. Wiss. Berlin, 



1831 (1832), p. 79; and Infus. (1838), p. 126. 



Plasma-body normally a soft irregularly-spherical or 

 ovate particle of animated protoplasm, having one or 

 more nuclei and pulsating vacuoles, but otherwise struc- 

 tureless, and without any apparent investing membrane; 

 possessing inherent extensile and contractile power. 

 Locomotion effected by lobular expansions or extensions 

 of the hyaline ectoplasm, originating on any part of the 

 body-surface, and forming in some species broad lobes, 

 in others digitate processes, short or elongated (some- 

 times branching), active or rigid, blunt or sharply- 

 pointed. Endoplasm granular, semitransparent, in 

 some rare examples nearly opaque. In the quiescent 

 (encisted) state, according to Leidy, the body is purged 

 of food and other ingested matter, and becomes 

 uniformly globular or elliptic, and invested with 

 a structureless membrane. 



Individuals differ greatly in size as well as in vital 

 activity, but all have the same plastic body, more or 



