184 
DR. CARPENTER’S RESEARCHES ON THE FORAMINIFERA. 
containing a most complete Bibliography, — that I do not feel it necessary to offer more 
than a mere sketch, marking out the principal periods into which this History may 
be divided. 
The^r^^ period includes all the observations made and published in regard to these 
minute polythalamous bodies, from the time when they first attracted attention, down 
to the date (1825) when M. d’Orbigny grouped them together, as constituting a 
distinct type of structure. The observers whose labours during this period did most 
to prepare the way for their successors, were Soldani*. Fichtel and Moll'|~, Mon- 
tague:J:, and Denys de Montfort§. 
The second period commences with the presentation to the Academie des Sciences, 
in 1825, of M. d’Orbigny’s “Tableau Methodiqiie de la Classe des Cephalopodes in 
which he first separated these chambered shells, under the title of Foraminifera, from 
the Siphonifera ; still retaining the former, however, like the latter, as an order of 
Cephalopods. A large number of new forms were added l)y M. d’Orbfgny to the list 
of those previously known ; and he laid the basis of the classification which he has since 
more fully elaborated. No suspicion appears then to have crossed his mind, that 
the place of these bodies might be amongst the lowest, instead of among the highest, 
of the Invertebrata ; and if his determination of their Molluscous nature was based 
on any actual observations of these animals in their living state, it is certain that 
such observations must have been of the most superficial character. 
The third period, with which our knowledge of the true nature of the Foraminifera 
really commenced, is inaugurated by the discovery, first announced by M. Dujardin 
to the Academie des Sciences in June 1835, of the Rhizopodoiis nature of the animal 
of certain simple forms of Foraminifera, and, by inference, therefore, of that of the 
group generally ; and in the following year he demonstrated the essential identity 
between the Amoeba and other simple freshwater Rhizopods (described by Professor 
Ehrenberg among the Polygastric Animalcules) and the Cristellaria and similar 
composite forms of marine Foraminifera, which had been previously ranked among 
Cephalopod Mollusks|l. 
The general results of M. Dujardin’s observations was, that the animal body con- 
sists, in every instance, of a mass of sarcode, — a gelatinous, somewhat granular sub- 
stance, not enclosed in a distinct membrane, and capable of extending itself into 
threads of extreme tenuity ; that there is neither mouth nor digestive cavity, but that 
alimentary particles, received into the very substance of the body, are gradually 
incorporated with it ; and that both the introduction of these particles, and the move- 
* Saggio orittographico, overo osservazloni sopra la terra Nautiliche e Ammonitiche della Toscana. Sienne, 
1780. 
t Testacea microscopica allaque minuta ex generibus Argonauta et Nautilus, ad naturam picta et descripta. 
VIndob. 1798, 1803. 
X Testacea Britannica, or Natural History of British Shells. London, 180.3-1808. 
§ Conchyologie Systematique. Paris, 1808. 
II See Annales des Sciences Naturelles, 2 s4r., Zool. tom. iii. p. 312. 
