Prof. Eltrenherg's ResearcJies on tlie Infusoria. 81 



for their systematic subdivision. M. Ehrenberg has not resort- 

 ed for this purpose to the masticating organs which we have al- 

 ready seen attain in some (Hydat'ma and Philodina aculeata) 

 a high state of development, because their exposition is both ex- 

 ceedingly difficult and necessitates the destruction of the animal. 

 Good characters are also furnished by the nature of the rotatory 

 organs. 



The construction of these tables brings into view a principle 

 which has not been hitherto recognised, viz. that the naked in- 

 fusoria and those provided with a crustaceous or corneous cover- 

 ing, are intimately connected together, and very often entirely 

 agree with one another in external and internal structure, with 

 the single exception of the consistency of their coat. Two pa- 

 rallel series are thus formed, the Nuda and Loricata of Dr 

 Ehrenberg, answering to certain of the Gymnodes and Crustodes 

 of Bory St Vincent, which had been hitherto separated under 

 entirely distinct divisions. The number of the Infusoria Lori- 

 cata is very small among the Polygastrica, but bear a much more 

 equal proportion to the Nuda among the Rotatoria. The num- 

 ber of loricated polygastrica will be much increased if we refer 

 to the animal kingdom the family of the Bacillariae. This fa- 

 mily which stands in such close relations with some sea algae, 

 such as the Girodella, Schizonema and Micromega, and with 

 some of the small fresh-water algae, will most probably come 

 under this head by the demonstration of an absorption of colour- 

 ing matter into several internal stomachs in all the species of 

 the genus Arcella. A similar nutritive function has been ob- 

 served in two species of the genus Dijfflugia, so long hovering 

 between vegetable and animal life, viz. the proteiformis^ Le 

 Clerc, and a new species discovered by Dr Ehrenberg at Berlin 

 — the acuminata. 



TABLE. 



PUytozoa (Goldfuss). — Animalia Lifusaria (MUller).— ^wi- 

 maux Microscopiques (Bory St Vincent). 



OCTOBER DECEMBER 1831. 



