46 CLAvSS I. 



Family II. Amcebcea. Animalcules naked, emitting and retract- 

 ing irregular, mutable lobes by continuous motion. 

 Amoeba EHRENB. (Proteus MUELL.) 



Sp. Amoeba diffluens EHRENB., Volvox Chaos L., Proteus diffluens MUELL. ; 

 ROESEL, Ins. m. Tab. ci. fig. A T ; x MUELL., In/us. Tab. n. fig. i . . . 12 ; 

 EHRENB., Infusionsih. Tab. vin. fig. xii. A gelatinous mass, of rounded 

 form, if the entire animal contracts itself on disturbance of the water ; 

 when the water becomes quite at rest the body extends itself variously 

 into lobes and processes, which are drawn in again. ROESEL observed 

 these parts to be even torn asunder by extension, so that there arose two 

 animals (Propagation by spontaneous division). The name Proteus had 

 been previously given (by LAURENTI) to a genus of Reptiles, and was on 

 that account changed into Amiba 2 by BORY, and into Amoeba by EHREN- 

 BERG. [Perhaps Amoeba is a temporary state of other forms, as of the 

 shelled Rhizopods, &c. Vid. LIEBERKUEHN, in MUELLER'S Archiv. 1854, 

 s. 17, and COHN in SIEBOLD and KOELLIKER'S, Zeitschf. Wissensckaft. Zool. 

 Bd. iv. s. 262.] 



Family III. Arcellina. Animalcules enclosed in a membranous 

 lorica or calcareous test, partly exsertile from their covering, and 

 emitting processes sometimes filiform and branched. 



They are small calcareous forms (shells) divided into cells, found 

 in sea-sand and in a fossil state in the Chalk-formation, and espe- 

 cially in the coarse tertiary limestone. These miscroscopic crea- 

 tures occur in incredible numbers, 6000 of them having been 

 counted in an ounce of sand from the Adriatic sea, whilst an 

 ounce from the shore of the Antilles contains, by computation, near 

 four millions. They were investigated at the end of the last cen- 

 tury by SOLDANI, and in the present by FICHTEL and MOLL, and 

 afterwards especially by D'OnBiGNY, who defined more than 1600 

 species of them. Until within a few years these bodies were refer- 

 red to the Molluscous Division, genus Nautilus L. (Cephalopoda, 

 vid. the first edition of this Manual, n. pp. 107, 108). Recent 

 observations, however, consign these Polythalamia or Cellulacea to 

 a much lower position, near the genus Proteus of Mueller. Although 

 D'ORBIGNY has been satisfied by the investigations of DUJARDIN 

 that these animals do not belong to the Molluscs, he still believes 

 that they ought to be considered as a distinct class of the animal 

 kingdom (standing between the Polyps and Echinoderms), and 

 calls them Foraminifera, the same name under which he formerly 



1 BORY DE ST VINCENT and DUJARDIN refer these figures to another species, sup- 

 posed to differ from Proteus diffluens by its greater size. 



2 Dictionn. duss. d'Hist. natur. I. 1822. p. 261. 



