84 ORGANJZA TION OF THE INFUSORIA. 



marine Acinete form has been recorded by Lachmann. Opinions with respect 

 to the functions of the trichocysts of the Infusoria are not entirely in accord, 

 some relegating to them, as with the thread-cells of the Ccelenterata, an 

 offensive and defensive, and others a simply tactile property : the balance 

 of evidence would appear to be in favour of the former interpretation. 



Amylaceous Corpuscles. 



Those bodies of an apparently amylaceous or starch-like nature, included 

 under the above title, possess a very limited distribution, occurring, so far 

 as is at present known, only among the Flagellata and in relationship 

 with the family of the Euglenidae, already cited as most conspicuously 

 distinguished for the possession of eye-like pigment-spots. In the genus 

 Englena, which is especially remarkable for the development of these 

 structures, they are found, moreover, to present a distinct and varied form 

 in the separate species, which consequently derive from their posses- 

 sion supplementary characteristics of some value for specific diagnosis. 

 The more ordinary contour of these amylaceous corpuscles is oblong or 

 elongate-quadrate, but varies in such types as Euglena acus and E. deses 

 to bacillate, or even acicular. In some forms, such as E. spirogyra and 

 E. oxyurus, there are more usually only two such corpuscles, one at each 

 extremity, of large size, and exhibiting a more opaque centre and pellucid 

 external zone, while in the two first-named types they are more generally 

 numerous, and present a homogeneous and semi-opaque consistence. In 

 certain instances they appear to multiply by division within the animalcule's 

 body, and, contrary to the structures previously described, appear to lie 

 loose within the central endoplasmic element, instead of being enclosed 

 inside the cortical layer or ectoplasm. The precise nature and significance of 

 these peculiar bodies have yet to be elucidated. 



Decomposition or Diffluence. 



Some remarkable phenomena connected with the manner in which, under 

 various uncongenial conditions, the soft sarcode bodies of the Infusoria 

 become more or less rapidly disintegrated, require brief notice. Artificially, 

 through the addition to the water of a little ammonia or other reagent, 

 or naturally, by permitting the same water to evaporate, certain species 

 possessing a non-indurated integument, such as the representatives of the 

 genera Oxytricha, Trichoda, and Enchclys, may be observed to fall bodily 

 to pieces, or, decomposition commencing at one point gradually spreads 

 throughout the entire organism, granular or globular portions becoming 

 successively detached, until at length the entire body has been as it were 

 consumed. At any point, however, by the addition of a fresh supply of 

 oxygenated water, this action of decomposition may be permanently 

 arrested, and the animalcule, or such larger portion or portions of it 



