FLAGELLATA 765 



take 011 a ramifying arrangement. While some of these composite 

 organisms are sedentary, others, as Dinobryon, are free-swimming. 



Two solitary flagellate forms, Anthophyaa and Anisonema, may 

 he specially noticed as presenting several interesting points of 

 resemblance to the peculiar type next to be described, the most 

 noticeable being the presence of a distinct mouth and the possession 

 of two different motor organs one a comparatively stout and stiff 

 bristle, of uniform diameter throughout, which moves by occasional 

 jerks, and the other a very deljcate tapering flagellum, which is 

 in constant vibratory motion. If, as appears from the observa- 

 tions of Biitschli. the well-known Astasia of which one species has 

 a blood-red colour, and sometimes multiplies to such an extent as 

 to tinge the water of the ponds it inhabits has a true mouth for the 



FIG. 586. Codosiga nmlMata: Colony-stock, springing from single 

 pedicel tripartitely branched. 



reception of its food, it must be regarded as an animal, and sepa- 

 rated from the Euylena (with which it has been generally associated), 

 the latter being pretty certainly a plant belonging to the same 

 group as Volvos. 1 



There can be no longer any doubt that the well-known Noctilnca 

 miliaria to which is attributable the diffused luminosity that fre- 

 quently presents itself in British seas is to be regarded as a gigantic 

 type of the ' unicellular ' Flagellata. This animal, which is of sphe- 

 roidal form, and has an average diameter of about g^th of an inch, 

 is just large enough to be discerned by the naked eye when the water 

 in which it may be swimming is contained in a glass jar held up to 



1 See the memoir by Prof. Biitschli in Zeitschrift f. Wissensrli. Zool. Bd. xxx., 

 of which an abridgment (with plate i- given in Quart. Jo urn. Micros. Sci. vol. xix. 

 1H79, p. 63. 



