REBOUILLIA. 



[ 654 ] 



REPTOMONAS. 



from the anterior margin ; foot decurved, 

 lunate; freshwater; length 1-288". 



BiBL, Ehrenberg, Infus. 448 ; Pritchard, 

 Infusoria, 088. 



■REBOUIL'LIA, Raddi. — a genus of 

 Marchantieae (llepaticne), founded ou Mar- 

 chantia hemisphcrrica, Linn., characterized 

 by the conical or tlattened,l— 5-lobed stalked 

 receptacle ( fig. 610), the perigone being ad- 

 herent to the lobes of the receptacle on the 

 under side, opening by a slit (fig. 617) ; 



Fig. 616. 



Fig. 617. 



Hebouillia hemisphsBrica. 



Female recp]itacles, with the perigone burst. 



Fig. 616, seen from above; Fig. 617, from below. 



Magnified 2 diameters. 



perichsete none, and the globose sporange 

 liursting irregularly. The antheridia are 

 imbedded in sessile, crescent-shaped disks. 

 The fronds are rigid, with a well-marked 

 midrib, green above, purple beneath. It 

 grows on moist banks, or by the side of 

 mountain-streams. 



BiBL. Hook. Br. FI. ii. pt. 1. 108 ; Bis- 

 choff, JV^ova Acta, xvii. 1001, pi. 69. fig. 1 ; 

 Endlich. Gen. Plant. No. 408. 



RECEPTACLES FOR SECRETIONS. 

 See Skceeting Organs of Plants. 



RED SNOW.— The remarkable pheno- 

 menon Imown under this name has been the 

 subject of very extensive investigation, and 

 it is well known to be the result of the 

 enormous development of a microscopic 

 organism related to Protococciis or Chlami- 

 dococcus inridis. We are inclined to believe 

 that more than one 1'orra is comprehended 

 at present under the name of Protococciis or 

 Ilcematococcus nivalis ; for our specimens of 

 Arctic red snow, for which we were in- 

 debted to the kindness of R. Brown, appear 

 to belong to the same genus as Palmella 

 crucnta, as first indicated by Brown, and 

 confirmed by Sir W. Hooker. Greville's 

 figures of the Scotch plant closely resemble 

 this ; but the continental plants described by 

 Shuttleworth and others would seem conge- 

 ni>vic with Protococciis, Chlamidococcus, and 

 Chlamidomonas, since they produce active 

 zoospores, the forms which Shuttleworth 



described as distinct Infusoria, as species of 

 Astada. Nearly connected with this con- 

 tinental snow-plant, if not identical, is the 

 Protococciis pi uvialiSjdLtiSiixihQ^ so elaborately 

 by Colin, which moreover appears to be 

 synonymous with the Uiscercea jmrpurea of 

 Morren. 



The following is a description of the red 

 snow, brought home by Capt. Parry, from 

 our own observation. It may be noticed as 

 remarkable that, after being kept so many 

 years in a moist state in a stoppered bottle, 

 the structure appears almost unchanged, the 

 only difierence being the assumption of a 

 gieen colour on the surface of the masses 

 when exposed to light. Frond an indefinite 

 gelatinous mass densely filled with splierical 

 cells, about 1-200" in diameter (PI. 7. fig. 

 3f/) ; cells with a distinct membrane, their 

 contents consisting of numerous tolerably 

 equal granules, red or gi'een (see above). 

 Between the large cells lie patches of mi- 

 nute red granules (as in Palmella crnenta, 

 PI. 7. fig. 8 a, b), apparently dischai'ged from 

 the large ceUs. Bauer and Greville both 

 i describe this as the mode of propagation of 

 the plant ; but it is probable that the cells 

 also increase by division when actively ve- 

 getating. 



BiBL. Brown, Appendi.v to Posses 1st 

 Voyage, 1819; DeCandolle, Bihl. miiv. 

 Geneve, 1824 : Hooker, Append, to Parry's 

 Second Voyaye ; Greville, Crypt. Fl. pi. 'I'-M ; 

 Shuttleworth, Bihl. univ. Geneve, 1840; 

 Morren, Mem. Acad. Bruxelles, xiv. 1841 : 

 PTotow, j\orrt Acta, xx. 11; Cohn, Nova 

 Acta, xxii. (305. 



R1]NULI'N.\, Blake.— Minute subglo- 

 bular, hollow, calcareous bodies, l-:200" in 

 diameter, often silicified, entering largely 

 iuio the composition of the Coralline Oolite ; 

 regarded as probably organic by Sorby, and 

 referred to the Foraminifera by Blake. 

 (Sorbv, Qa. Geol. Jn. vii. 1851, 1 ; Blake, 

 Jn. Mic. Soc. 1876, 202.) 



RENULI'TES, Lam. (Penulina, Blain- 

 ville). — A broad, reniform modification of 

 Vertebralina, one of the Porcellaneous Fora- 

 minifera. 



IJiJiL. Carpenter, Infrod. For. 74. 



RE'OPIIAX, Montlort.— A simple, uni- 

 serial subspeciesofZiYwo/a, straight or curved, 

 chahibers often angular or rugged in outline. 

 Abundant in manv seas. (Parker and 

 .Tones, Ann. N. II.\ vi. 340; Brady, Qu. 

 Mic. Jn. n. s. xix. 51.) 



REPTOMONAS, Kt.— A genus of Rhizo- 

 Flagellate' Infusoria. Creeping ; fiagellum 



