572 SYSTEMATIC HISTOKY OF THE INFUSORIA. 



This family has no corresponding one in the system of Dujardin. Some of 

 its members are represented in the family of the Enchelina as members of the 

 genera Acomia and EncJielijs. The genus Cijclidium (Duj.) is included among 

 the Monadina of that author (p. 497), and includes beings fui^nished with a 

 filament, but destitute of mouth and cilia — characters not at all analogous to 

 those given by Ehrenberg to his genus of this name. 



Perty, moreover, has not retained this family in his system, although he 

 accepts the genus Cyclidium, which he refers to a family called "■ Tapinia," 

 where it is associated with Acomia (Buj.), with Leucoplirys (Ehr.) or Tnchoda 

 (Duj.), and with the follo^ving newly-instituted genera: viz. AcropistMum, 

 Bceonidiumy Opistliiotricha, Siagontherium, and Mecjatricha, — a set of terms not 

 recommending themselves bj'-^ their euphony, and, we presume, not wanted in 

 a true systematic distribution to express distinct and independent forms of 

 ciliated Protozoa. However, to render our 7'esume complete, these presumed 

 new genera are appended to the family of Enchelia, to which several of their 

 species are referred by Ehrenberg. 



The family Cyclidina (Ehi\) would, in all probability, disappear from a 

 revised system of classification. Thus Cyclidium appears to be only an em- 

 biyonic phase of other animalcules, and Pantotrichum and Chcetomonas are 

 not sufficiently characterized and examined by Ehrenberg to enable us with 

 certainty to recognize them, or to determine their affinity. Moreover, the 

 beings brought together under these genera are, some of them at least, very 

 doubtfully referable to them, and have been so casually examined that their 

 identification would be difficult. The ova and the polygastric organization 

 mentioned in Ehrenberg's account are matters only of hypothesis. 



Genus CYCLIDIUM. — Body compressed discoid, provided with a simple 

 circular row of cilia. In G. Glaucoma alimentary vacuoles are distinct. The 

 mouth is a rounded opening, situated upon the under surface of the body, 

 either close at the anterior extremity, or towards the centre. The organs of 

 locomotion consist, as in Kerona and StylonycMa, of a number of cilia-like 

 feet, situated on the margin of the abdomen. It has been thought that 

 longitudinal lines, produced by rows of very delicate cilia, were present ; if 

 so, and an anal opening be discovered, C. Glaucoma would rank with the 

 Oxytrichina. Fission transverse. Since Ehrenberg wrote these observations, 

 Lachmann has described not only a mouth, but also an anus on the ventral 

 siu'face near the posterior extremity. This statement, taken in connexion 

 with another, that some at least of the forms of Cyclidium are embryonic 

 stages of other animalcules, leaves this genus in the greatest uncertainty both 

 as to its independent existence and its systematic position. 



Cyclidium Glaiwoma (M.). — Oblong- 

 elliptic, abdomen fringed with cilia ; 

 delicate longitudinal strise are observed 

 upon the back. In swimming, it re- 

 sembles Gyrinns, or Notonecta, a well- 

 known little black water-beetle (see 

 3Iicroscopic Cabinet, pi. 4). Sometimes 

 the movement is very quick ; at other 

 times the animalcules remain for a while 

 stationai-y, and then presently spring 

 vdih. a curvetting motion to another 

 vspot. Fonnerly this species was con- 

 founded with Glaucoma scintillans, but 

 is much smaller (x. 209 is a side view, 

 showing the cilia ; fig. 211 a dorsal view : 

 and fig. 210 a specimen undergoing trans- 



verse self-division). They are repre- 

 sented as fed with indigo. Abundant 

 in vegetable infusions in the spring. 

 1-2880" to 1-1150". 



Betwixt this species and Enchelys 

 nodulosa (Duj.) there is a complete 

 agreement. The body, on a transverse 

 section, is triangular ; hence it is (says 

 Perty) that Dujardin has described it as 

 sometimes assuming a triangvdar form. 

 Chlorophyll granides are occasionally 

 seen interaally. Stein identifies the 

 embryo of Chilodon Cuculhdus with this 

 species of Cyclidium, which he would 

 tliereforc exclude from the category of 

 independent animalcules. Internally;this 



