CERATIDIUM. 



[ 153 ] 



CERCOMONAS. 



C. turgidus Biddulphia turgida ; C. 

 Smithii = Eupodiscus radiatus ; C. Ice vis = 

 Biddulphia levis; C. thermalis. 



BIBL. Ehrenberg, Ber^Berl. Ak. 1843, 

 270 ; Rabenhorst, Fl. Alg. i. 313. 



CERATID'IUM. Ehr. A genus of In- 

 fusoria, of the family Oxytrichina. 



Char. Furnished with cilia, horns on the 

 fore part of the body, but neither hooks nor 

 styles. 



One species, C. cuneatum. Dujardin con- 

 siders this to have been a mutilated Oxy- 

 tricha. The appearance of horns arises from 

 the anterior part of the body being deeply 

 notched. 



BIBL. Ehr. In/us.; Dujardin, Inf. 421. 



CERA'TIUM. A genus of Isariacei (Hy- 

 phomycetous Fungi) containing a generally 

 diffused British plant, C. hydnoides, which 

 grows on rotten wood as a tuft of white 

 simple or slightly branched oblong processes, 

 which produce on their surface sterigmata 

 (spicules, Berk.\ each of which is sur- 

 mounted by a spore which easily falls off. 

 The whole plant readily collapses into a 

 mucilaginous mass. The cellular appear- 

 ance figured by Greville depends on the 

 collapsing of the processes. 



BIBL. Berk. Hook. Br. Fl. ii. pt. 2. 329; 

 Grev. Crypt. FL pi. 168. 



CERA'TIUM, Schrank. A genus of 

 Cilio-flagellate Infusoria = Peridinia with 

 horns. 



CERATOCLA'DIUM, Corda. A genus 

 of Hyphomycetous Fungi ; consisting of a 

 single species, C. microspermum (fig. 349), 

 characterized by the erect, septate horny 

 threads, clothed with a pallid stratum 

 bearing simple sporophores (basidia), 

 terminated by a single staff-shaped 

 spore. 



BIBL. Corda, Prachtjl. pi. 20. 



CER'ATODON, Bridel. A genus of 

 Pottiaceous Mosses. 



C. purpureus, very common on banks and 

 walls, seta purple-red; C. cylindricus, seta 

 pale. 



BIBL. Wilson, Bryolog. Br. 83 ; Berkeley, 

 Brit. Moss. 274. 



CERATONE'IS, Ehr. A genus of Dia- 

 tomacese. 



Char. Frustules cymbiform, free, with a 

 more or less distinct central nodule, the 

 apices rostriform and produced. 



Smith places the British species in other 

 genera, thus : 



C. arcus=Eunotia arcus- C. closterium 

 = Nitzschia cl. ; C. fasciola = Pleurosigma 



fasc. ; C. gracilis= Nitzschia tcenia ; C. Ion- 

 gissima Nitzschia birostrata. 



Rabenhorst admits C. arcus, C. amphioxys, 

 and C. toxon (Perty). 



BIBL. Ehr. Ber. d. Berl. Ak. 1839, 1840 

 et seq. ; Kutz. BacilL and Sp. Alg. ; Smith, 

 Br. Diat. ; Rabenhorst, Fl. Alg. i. p. 76 j 

 Perty, Lebensf. p. 205. 



CERATO''NIA, Linn. A genus of Le- 

 guminosae (Flowering Plants). The pods 

 and seeds or beans of C. siliqua the Carob- 

 or Locust-tree of Spain, are used for adul- 

 terating coffee. PI. 2. fig. 8, , 6, repre- 

 sent the characteristic tissues of the pod ; 

 e and d, those of the bean. 



CERATOP'TERIS, Brongniart. A ge- 

 nus of Pterideae (Polypodiaceous Ferns). 

 Exotic. The inrolled margin of the leaf 

 simulates an indusium. 



C. thalictroides ; tropics (figs. 226-7 

 thecae, 228-30 spores). 



BIBL. Hook, Fil. Syn. p. 174. 



CERCA'RIA, Miill. These organisms 

 were formerly regarded as constituting a 

 genus of Infusoria, but are now known to 

 consist of the larvae or nurses of Trematoda, 

 as Distoma, &c. 



The body is oblong,depressed, changeable ; 

 the mouth subterminal, armed or unarmed. 

 Acetabulum subcentral. Tail filiform, sim- 

 ple, attenuate at the apex, deciduous. 



They are found parasitically on the body, 

 or within the intestines, liver, ovaries, &c. 

 of Mollusca (Lymntcus, Planorbis, &c.) ; and 

 may be obtained by wounding the body in 

 water. 



C. furcata (PL 51. fig. 32). On Lymnaus 

 stagnaliSj in autumn ; length 1-12". C. he- 

 lids viviparce, in the liver of Pahidina vivi- 

 para. C. planorbis, in the ovaries of Pla- 

 norbis corneus and marginatus. 



Diesing describes 12 " species." See 

 DISTOMA. 



CERCO'MONAS, Duj. A genus of Fla- 

 gellate Infusoria. 



Char. Free, body rounded, discoidal or ob- 

 long, sometimes tuberculated, with a va- 

 riable posterior prolongation in the form of 

 a tail, which is longer or shorter and more 

 or less filiform (PL 30. figs. 22, 23). 



Dujardin remarks that the only absolute 

 difference between the Cercomonads and 

 the Monads consists in the presence of the 

 posterior prolongation, which is formed by 

 the substance of the body becoming agglu- 

 tinated to the slide, and more or less drawn 

 out so as to form sometimes merely a tuber- 

 cle, at others an elongated tail, or a filament 



