INFUSORIA. 



[ 347 ] 



INFUSORIA. 



Even in infusions of many powerful poisons, 

 as of Nux vomica, Cevadilla, &c., they will 

 not be found absent ; and Dujardin has no- 

 ticed that their development is greatly pro- 

 moted by the addition of certain salts to the 

 solutions, as phosphate and carbonate of 

 soda, phosphate, nitrate, and oxalate of am- 

 monia ; and this author is inclined to believe 

 that some of these salts become decomposed 

 in the presence of the organic matters, 

 yielding nitrogen to the Infusoria; he also 

 states that oxalate of ammonia disappears 

 entirely under these circumstances. We 

 believe, however, that a process of oxidation 

 goes on in many of these cases, unconnected 

 with the presence of the Infusoria, and thus 

 salts of vegetable acids become converted 

 into salts of more highly oxidized acids, as 

 into carbonates, &c. 



The following are the most common of 

 the Infusoria found in natural waters or infu- 

 sions of vegetable or animal matters : 



Amphileptusfasciola. 

 Bodo saltans. 



socialis. 



Chilodon cucullulus. 

 Chilomonas parame- 



cium. 

 Chlamidomonas pul- 



visculus. 

 Coleps hirtus. 

 Colpoda cucullus. 

 Cyclidium glaucoma. 

 Euplotes charon. 

 Glaucoma scintillans. 

 Leucophrys carnium. 



pyriformis. 



Monas crepusculum. 

 gliscens. 



Monas guttula. 



termo. 



Oxytricha pellionella. 

 Paramecium aurelia. 



chrysalis. 



colpoda. 



milium. 



Polytoma uvella. 

 Stylonichia pustulata. 



mytilus. 



Trachelius lamella. 

 Trichoda pura. 

 Trichodina grandi- 



nella. 



Uvella glaucoma. 

 Vorticella convallaria. 

 microstoma. 



Some of the Infusoria are phosphorescent, 

 and impart a luminous property to sea- 

 water. The following are the species in 

 which this has been distinctly observed : 

 Prorocentrum micans ; Peridinium michaelis, 

 P. micans, P.fusus, P.furca, and P. acu- 

 minatum ; Synchceta baltica, and a doubtful 

 species of Stentor. 



Slender needle-like crystals of sulphate of 

 lime have been observed affixed to the bodies 

 of the Infusoria, probably derived from the 

 water in which they live. 



The Infusoria are difficult of preservation. 

 Some of them will exhibit their characters 

 when dried; the cilia and vacuoles remaining 

 very distinct, as also the striae upon the in- 

 tegument. Others are but little changed 

 by a concentrated solution of chloride of 



calcium. Solution of chromic acid or of 

 bichloride of mercury will answer with some 

 of them, although they are rendered some- 

 what opaque by these reagents, which is 

 sometimes an advantage where they are 

 naturally very transparent. 



The systematic arrangement of the Infu- 

 soria is in an unsettled state. The characters 

 of the genera and species laid down by Eh- 

 renberg are mostly founded upon analogies 

 more than upon observation. Those pro- 

 posed by Dujardin, on the other hand, are 

 far more accordant with observation, and 

 consequently more simple and practical. 

 But unfortunately the latter author has so 

 altered the names proposed by Ehrenberg, 

 and since generally adopted, raking up old 

 and long-forgotten names, which are, more- 

 over, often doubtfully identical with those for 

 which they are substituted, and sometimes 

 using similar names for totally different ge- 

 nera and species, that great confusion has 

 been produced, and the two systems are not 

 at present reconcilable. We are therefore 

 compelled to give both of them. 



In descriptions of genera and species, the 

 anterior part of the body is that near which 

 the eye-specks are situated, and which is 

 directed forwards ; the surface towards which 

 the eye-specks are nearest forms the back or 

 dorsal surface. A narrowing of the body 

 posteriorly, so as to give rise to a prolonga- 

 tion, forms a tail ; and an anterior prolon- 

 gation of the dorsal surface is described as a 

 forehead or upper lip, according to its situation . 



Ehrenberg 1 s Classification. Ehrenberg 

 divided the Infusoria into two classes, the 

 Rotatoria, which now form a distinct class 

 of the Invertebrata, being much more highly 

 organized than the Infusoria ; and the Poly- 

 gastrica, which correspond to the Infusoria 

 as at present recognized, excluding, however, 

 the following families. 



The MONADINA we leave as doubtful; 

 but they consist beyond a doubt of the zoo- 

 spores of Algae, or the lower forms of Algae, 

 and the germs of true Infusoria. 



The CRYPTOMONADINA and HYDROMO- 

 RINA probably consist of Alga3, like some 

 of the last. 



The VOLVOCINA form a family of Con- 

 fervoid Algae. 



The VIBRIONIA are included among the 

 OSCILLATORIACE^E (Confervoid Algae). 



The CLOSTERINA form a subfamily of 

 DESMIDIACE^E (Confervoid Algae). 



The BACILLARIA' correspond to the DES- 

 and DIATOMACE^E (Algae). 



