PAPER, METEORIC. 



[ 490 ] 



PARAMECIUM. 



on a slide . The determination of the nature 

 of the filaments of which a paper is com- 

 posed, by the aid of the microscope, would 

 require a very thorough knowledge of the 

 characters of vegetable fibres, and we should 

 imagine could scarcely be very decisive in 

 most cases, except so far as distinguishing 

 between classes of substances, as between 

 parenchymatous and filamentous or fibrous 

 substances, &c. 



Rice-paper, as it is termed, is a totally 

 different material, consisting of thin layers, 

 cut by a peculiar operation, of the pith of 

 Aralia papyrifera, a Chinese Araliaceous 

 tree; this consists of parenchymatous cel- 

 lulose tissue. 



Papyrus, consisting of pressed superposed 

 laminae of the pith of Papyrus plant {Pa- 

 pyrus antiquorum, a kind of Sedge), exhibits 

 the lax parenchymatous structure character- 

 istic of similar tissues, such as the pith of 

 Rushes, &c. 



PAPER,METEORTC,andAEROPHYTES. — 



The structm-e and origin of these substances 

 are the same as that of the so-called natural 

 fiannel (Flannel). They were formerly 

 regarded as of meteoric origin. They have 

 been observed in some instances to fall from 

 the air, having been wafted perhaps many 

 miles from their place of formation by whirl- 

 winds and hurricanes. 



BiBL. Ehrenberg, Abhandl. d. Berl.Akad. 

 1838. 



PAPULASPORA, Preuss.— A genus of 

 Mucedines (Hyphomycetous Fungi) consist- 

 ing of a decumbent articular mycelium, 

 sending up erect pedicels, bearing a collec- 

 tion of oblong erect spores, which spores are 

 bi- or quadrilocular. 



P. sepedonioides has been found on rice- 

 paste. 



BiBL. Berk, and Broome, Ann. Nat. Hist. 

 ser. 2. xiii. p. 462. 



PAPYRUS.— The pith of the stems of the 

 Papyrus antiquorum (modern papyrus from 

 P. syriacus), cut into slices, which are laid 

 upon one another and pressed so as to form 

 a compact stratum. Sections display the 

 parenchymatous tissue more or less deformed 

 by pressure. 



PARAMECIA or PARAMECINA, Duj. 

 — A family of Infusoria. 



Char. Body soft, flexible ; form variable, 

 usually oblong and more or less depressed ; 

 with a lax reticulate integument, through 

 which numerous vibratile cilia pass in regular 

 rows ; mouth present. 



The organisms included in this family 

 belong to the Ophrycercina, Enchelia, Tra- 

 chelina, and Colpodea of Ehrenberg. 



Dujardin distinguishes the genera thus : 



TBody round, prolonged in the form of a neck, with an appearance of a mouth at 



JMouth indistinct J the end 1 . Lacrymaria. 



or doubtful j Body oval-oblong, depressed, with a broad lateral orifice, from which a bundle of 



L filaments issues 2. Pleuronema. 



with a lip -like f lip longitudinal, vibratile ; body oval, depressed, broader behind. 3. Glaucoma. 



appendage I lip inferior, projecting ; body ovoid, sinuous or reniform 4. Colpoda. 



r I oblong, compressed, with a longitudinal oblique 



bodv never ' ^^^^ ^' ■P'''''''"*^^^^'"' 



Mouth lateral •{ „,;fi,^„+ „„ o-lnhnlar fusiform, greatly elongate and narrowed in front Q. Amphileptus. 



giouuidr .^,,^„f mouth with teeth 7. CMlodon. 



lamelliiorm, smuous •< ^.u -i-i. i. ^ i-u -> r i it 



y ' l mouth without teeth 8. Loxophyllum, 



Body ovoid or oblong, becoming r mouth with teeth 0. Nassula. 



^ globular by contraction t teeth absent 10. Pa?iophrys. 



Mouth terminal ; body ovoid or oblong, becoming globular by con- r mouth with teeth 11. Prorodon. 



traction. l teeth absent 12. Holophrya, 



without an 

 appendage 



no 



BiBL. Dujardin, Infus. p. 463. 



PARAMECIUM, Hill, Ehr.— A genus of 

 Infusoria, of the family Colpodea. 



Char. Body covered with cilia ; 

 spot ; a papilliform tongue-like 

 present. 



Ehrenberg describes eight species 

 being doubtful. 



P. aurelia (PI. 24. figs. 56 and 5/). Body 

 cylindrical, ovate-oblong, rounded or obtuse 

 at the ends, with an oblique longitudinal 

 fold extending to the mouth. Aquatic; 

 length 1-120 to 1-100". 



eye- 

 process 



two 



This common infusorium shows well the 

 curious star-shaped contractile vesicles. Eh- 

 renberg notices in it the periodical occur- 

 rence of small black crystalline particles at 

 the anterior end. The dei)ressions on the 

 surface of the integument (PI. 25. fig. 1) are 

 distinctly seen in the dried animal. 



P. chrysalis, E. {Pleuronema crassa, D.) 

 (PL 25. fig. 37, undergoing division). Body 

 oblong, cylindrical, oral cilia very long. 

 Aquatic ; length 1-240". 



P. Kolpoda, E.=the adult stage of Ko/pof/a 

 cucuUus, E. 



