170 Transactions of the 



Now, this Temporarily Fixed Division is represented by 

 CalUdina, Rotifer, Adinurus, and Philodina, -whicli though 

 nominally Free are specially organized to j)ermit them to assume 

 at will, either a Free or a Fixed position, and of maintaining these 

 positions respectively for periods of indefinite extent. The foot of 

 each incUvidual of this Division is furnished with a sucker extending 

 beyond the toes of the telescopic footstalk, which together constitute 

 a mechanical supjDort that may be exercised or released at will. 



This Temporarily Fixed Division, while it assimilates through 

 certain members of SECTION I. by reason of the vagrant habits 

 of the Floscules already referred to, differs, moreover, still further 

 from the Absolutely Free Division in one most important par- 

 ticular, viz. the possession of a single setigerous antenna which 

 distinctly removes it not only from the Free Division possessing no 

 such appendage, but furthermore from the Solitary Fixed forms 

 of SECTION I., which possess unexceptionally two antenna ; so 

 that the pseudo genus Cei)lialosi]plion with its specific title Limnias 

 of Ehrenberg's Classification (Plate LXXXI., Figs. 1 and 2), should 

 not be admitted into the Family in which it is unwittingly placed. 

 It belongs indisputably to this Temporarily Fixed Division, and 

 is generically a Philodine under conditions which at first might 

 appear abnormal, but which prove on a more intimate acquaintance 

 to be natural functions. 



The Philodines, moreover, are provided not only with the 

 secondary range of cilia which characterize the Fixed Division, but 

 also with a ciliated rudimentary i)ellect-cu/p in conjunction, which 

 they employ in building a floccose covering round about them, and 

 this conclusively associates them with this Division. With regard, 

 however, to the remaining members of the Family PniLODiNiEA 

 according to this proposed Division, I am not at this time prepared 

 to speak, and can only suggest it as a point for investigation worthy 

 of the attention of my fellow-workers. 



I have had numerous examples under observation throughout 

 the winter months for some years past, having broken the ice to 

 obtain them. Placed in a cool situation, they invariably remained 

 some hours and even days in this completely loricated condition ; 

 but as the warmth of the room, and that of the lamp while under 

 observation, began to be appreciated, palpable movements were first 

 manifested within the floccose covering, the orifice of which is 

 closed by a coalescence of the materials composing it, such as de- 

 scribed by Mr. Henry Davis, in reference to CEcistes longicornis : 

 they eventually, after shorter or longer periods of repose, wriggled 

 out of these temporary dwellings, declared themselves hona fide 

 Philodines, and swam freely and buoyantly around the field, 

 exhibiting distinctly their bilobed rotary organs, supplemented with 

 the secondary range of appropriating cilia, with the conspicuous 



