OF THE MONADINA. 



495 



Genus DOXOCOCCUS.— The Monads forming this genus differ from all 

 others of the family Monadina by the singularity of their motion, which may 

 be defined to be neither that of swimming nor of rotation, but a sort of roll- 

 ing over and over. In other particulars they are like other Monads : they 

 have the same unvarying form, and are destitute of the eye-speck, project- 

 ing Ups, and tail ; and self-division is simple and complete. Four species are 

 known. 



Doxbcoccus Globulus. — Subglobose 

 or ovate ; transparent as water ; easily 

 Imown by its tedious rolling motion j 

 mouth not discerned. In salt water. 

 1-860". 



D. 7'uber (xvin. 8). — Brick-red, glo- 

 bular, and opaque. Elirenberg appears 

 to doubt whether this animalcule be- 

 longs here (though its motion is very 

 peculiar) or to the genus Trachelomo- 



nas ; and he has not been able to satisfy 

 himself of the existence of a lorica. 

 Amongst Conferv^se, &c. 1-1720". 



D. Pulvismliis. — Green, perfectly (?) 

 globular, and opaque. Amongst Con- 

 fervas. Not exceeding 1-1280". 



D. inequalis. — Irregularly globular, 

 transparent, and covered with green 

 spots. Amongst Confervae. 1-2400". 



Genus CHILOMONAS (XYIII. 14, 18).— Characterized by the obHquity 

 of the mouth with respect to the longitudinal axis of the body, which occasions 

 a projection above the mouth of a lip-like appearance. Motion in the dii'ection 

 of the long axis of the body ; form invariable ; devoid both of eye-speck and 

 tail. Whether the projecting hp is furnished with cilia, or with a double 

 filament, Ehrenberg has not satisfactorily determined, except in the case of 

 C. Paramecium, in which he states two filaments are to be clearly seen. On 

 C. destruens there are a number of indistinct cilia. Self- division is simple and 

 complete. 



Dujardin's characters of this genus are, "Animals with an ovoid, oblong 

 body, obhquely notched in front, with a very slender filament proceeding from 

 the bottom of the notch. Movement from before backwards, on its centre. 

 It is with doubt that I refer the Infusoria I thus name to the genus Chilo- 

 monas of Ehrenberg. The mode of insertion of the filament behind a pro- 

 jecting lip-like portion, approaches the animals to the Euglence and to certain 

 Thecamonadina ; but I cannot discover any trace of an integument, either 

 contractile or resistant." 



Chtlomonas Volvox. — Ovate, attenu- 

 ated and trimcated anteriorly, trans- 

 parent and coloiu-less ; projecting lip 

 long ; wiU feed on indigo. In stagnant 

 water. 1-1440". 



C. Parmnechwi (xviii. 14). — Oblong 

 or ovate, wider at one end than at the 

 other, keeled longitudinally ; colom* like 

 that of dirty water. The contained gra- 

 nules have the reaction of starch. At the 

 posterior end a clear nucleus with a red- 

 dish halo may be observed ; and at the 

 anterior is areddish vesicle, probably con- 

 tractile. It refuses colom-ed food. This 

 animalcule is easily distinguished by its 

 shape and peculiar lip-like process. With 

 a power of about 240, numerous vesicles 

 are visible, and with 380 the two fila- 

 ments, which are half the length of the 

 body, and proceed from a sinus in the 

 wider end. It moves in the direction of 

 its long axis, in a fluctuating or waver- 



ing manner. It sometimes clusters. In 

 water wherein wheaten bread has been 

 steeped. 1-1020". The coloiu-less va- 

 riety of this species is enumerated by 

 Perty as one of the many fonns of his 

 Cryptomonas polymorpha. 



C. destruens. — Oblong, but variable in 

 form, on accoimt of its softness, nearly 

 colourless or faint yellow. In salt and 

 fresh water, and in the bodies of dead 

 Rotatoria, e. g. Anurcea foUacea and 

 Monocerca Rattus. 1-860". 



C. granulosa (Duj.) (x\t:ii. 18). — Co- 

 lourless, oblong, larger anteriorly, al- 

 most invariable in form, although of ge- 

 latinous consistence ; filled with gramdes 

 which seem to project from its surface ; 

 filament very fine, arising from an ob- 

 lique notch. 1-940" to 1-850". 



C. obliqua. — Ovoid or pyriform, no- 

 dular, of variable form ; the filament la- 

 teral. 1-2600". 



