603 



SYSTEMATIC HISTOKY OF THE IN'FUSOEIA. 



illustrated in fig. 64, a-k. In stagnant 

 water. 1-430". 



E. infuscata. — Oval or spherical ; 

 whitish ; mouth not prominent, encircled 

 by a brownish ring. When fed with 

 indigo, numerous vacuoles become filled. 

 In bog- water. 1-280" to 1-240". 



E. nehulosa (M.). — Ovate, hyaline ; 



mouth projecting. This species receives 

 caraiine and indigo very readily. 1-230" 

 to 1-570". ' ■ 



E. nodulosa {J)\\y^ •= Cyclidium Glau- 

 coma (Ehr.). E. triquetra (Duj.) is a 

 mere accidental variety of the same 

 animalcule. 



Genus DISO!MA (?). — Body double, destitute of cilia ; oral extremity 

 truncated (direct) ; mouth ciliated, devoid of teeth. Within the bodies 

 numerous little vesicular cells (stomachs) are observed, and the discharge of 

 excrement may be seen to take place at the posterior extremity of each body. 



As already noticed, this is a very imperfectly-examined and doubtful 

 genus. The being described may be interpreted as one undergoing longitu- 

 dinal fission ; but there is no one character given, adequate to determine to 

 what family of animalcules it would be referable. 



DisoMA vacillans consists of two 

 clavate and filifonn corpuscles, hyaline, 

 and attenuated at the anterior extremity. 

 Ehrenberg remarks, *' Both bodies fre- 

 quently swam parallel beside each other, 

 and turned on their long axis, moving 



onwards quickly, though in a vacillating 

 manner ; sometimes both bodies gaped 

 widely apart from each other, but never 

 so ^^ddely as to form a straight line. 

 1-380". ' On Mount Sinai, Arabia. 



Genus TRICHODA. — Body devoid (?) of hairs or cilia : without a con- 

 striction or neck; mouth obliquely truncated, destitute of teeth, but pro- 

 vided Ts-ith vibratile cilia, and a Kp. Coloiu'ed food is received ; the anal 

 orifice is at the posterior extremity. The oblique direction of the mouth 

 gives rise to a very characteristic upper-lip-like projection. In T. Pijrum 

 only has self-division been observed. All the species are coloiuiess. 



In the system of Dujardin there is both a family Trichodina and a genus 

 I'richoda. Spealdng of the relations between them and the genus Triclioda 

 of Ehrenberg, he observes : " M. Ehrenberg has placed in his family Enchelia 

 a genus Triclioda, which in part corresponds with ours ; and he has, besides, 

 dispersed among Leucoj^hri/s, Encheli/s, Trachelius, Loxodes, <S:c., many Infu- 

 soria which we have brought together in this family (viz. Trichodina) ; but, 

 unlike him, we are unable to see their digestive organs." 



The Trichodina are soft, variable, flexible animalcules, ciliated, and have 

 either an evident mouth, or one indicated by a varpng arrangement of longer 

 cilia. Dujardin would have it understood that this family is only pro\asional ; 

 to comprise a tribe of animals intermediate in organization between the 

 Enchelina — the most simple of ciliated — and the Keronina, which conduct to 

 the highest forms of infusorial life, having defined mouths, and an armature 

 of styles, hooks, &c. The genera included by Dujardin in this family are 

 Triclioda, Trachelius, Acineria, Pelecida, and Dileptus ; the last two having a 

 higher grade of organization. The first-named is thus described : — 



Genus Triclioda (Duj,). — Ovoid-oblong, or pyriform, rather flexible ante- 

 riorly, \nih. a row of cilia directed backwards, and appearing to indicate the 

 presence of a mouth. Their surface does not appear reticulated, or ciliated in 

 rows, as it is in Acomia and Encliehjs. The Triclioda are chiefly found in 

 putrid infusions and in stale marsh-water. 



TmcHODA pura (Kolpoda Pyrum, 1 sions ; usually with Cyclidium Glaucoma. 

 M.). — Oblong, club-shaped, attenu- I 1-720". 



ated anteriorly ; mouth laterfd ; vacu- i Tliis species closely resembles Leiico- 

 oles small. Common in vegetable infu- I phrys pyriformis, which is somewhat 



