REPRODUCTION. 



[ 550 ] 



RHIPIDOPHORA. 



increase by division when actively vegetating. 

 Like the rest of the unicellular Algae, this 

 plant requires a new and thorough investi- 

 gation, for no characters are of any service 

 without a complete history of the develop- 

 ment. We subjoin references to the most 

 important papers on this subject. See also 

 WATER, COLORATION OF. 



BIBL, R. Brown, Appendix to Ross's First 

 Voyage, London, 1819; Bauer, Quarterly 

 Journal of Lit. Sciences and Arts, vii. p. 222; 

 Agardh, Nova Acta, xii. p. 2, System. Alg. 



?. 13; DeCandolle, Bibl. univ. de Geneve, 

 824 ; Nees v. Esenbeck, German ed. of R. 

 Brown's Works, i. p. 571 (abundant cita- 

 tions of older writers) ; Hooker, Append, to 

 Parry's Second Voyage ; Greville, Sc. Crypt. 

 Fl. pi. 231 ; Shuttle worth, Bibl. univ. Ge- 

 neve, Feb. 1840; Desmazieres, Ann. des Sc. 

 nat. 2 ser. xvii. p. 91 ; Meyen, Wiegmann's 

 Archiv, 1840. i. p. 166, transl. in Ann. Nat. 

 Hist. vii. p. 245 ; Morren, Hydrophytes de 

 Belgique, Mem. Acad. Bruxelles, xiv. 1841 ; 

 Von Flotow, Nova Acta, xx. p. 1 1 ; Cohn, 

 Nova Acta, xxii. p. 605. 



REPRODUCTION. Some observations 

 upon the reproduction are made under the 

 respective heads of the classes, orders, and 

 families to which the organisms belong. See 

 also CELLS and OVA. 



RESERVOIRS FOR SECRETIONS, 

 IN PLANTS. See SECRETING ORGANS, of 

 Plants. 



RETE MUCOSUM. See SKIN. 



RETICULARIA, Bull. A genus of 

 Myxogastres (Gasteromycetous Fungi), cha- 

 racterized by the indeterminate, thin, simple 

 peridium, bursting irregularly., with the 

 branched, shrubby, reticulated capillitium 

 adherent to it. Several species are British; 

 they are rather large plants, growing over 

 recently felled timber or on hollow trees, 

 rails, &c. 



BIBL. Berk. Brit. Flor. ii. pt. 2. p. 308 ; 

 Fries, Summa Veg. p. 449, Syst. Mycol. iii. 

 p. 83. 



RETINA. See EYE, p. 252. 



RHABDITIS, Duj. See ANGUILLULA. 



RHABDONEMA, Kiitz. A genus of 

 Diatomaceae. 



Char. Frustules tabulate, depressed, fixed 

 by a stalk arising from one of the angles, 

 with interrupted vittae (front view), vittae 

 capitate; valves transversely striate, striae 

 extending into the front view, and forming 

 numerous longitudinal series. Marine ; upon 

 Algse. Striae visible under ordinary illumi- 

 nation ; the dark lines or vittae correspond 



to more or less complete internal septa; 

 frustules connected with each other by gela- 

 tinous cushions (isthmi). 



R. arcuatum (Striatella arcuat., Ralfs) 

 (PI. 13. fig. 18). Vittae in two marginal 

 rows, isthmi convex. Length 1 -300". 



R. minutum (Tessella catena, Ralfs). 

 Vittae in two marginal rows ; transverse striae 

 faint. Length 1-1200 to 1-960". 



R. adriaticum. Vittae forming four rows 

 (interrupted in the middle, and again between 

 the middle and the margin on each side) ; 

 transverse striae distinct; isthmi concave. 

 Length 1-480 to 1-170". 



BIBL. Kiitzing, Bacill. 126, and Sp. Alg. 

 1 15 ; Ralfs, Ann. Nat. Hist. xi. 455, and xii. 

 104. 



RHAPHIDOGLCEA, Kiitz. A genus of 

 Diatomaceae. 



Char. Frustules navicular, arranged in 

 radiating crowded rows in a globose gelati- 

 nous mass. Marine. 



R. micans (PI. 14. fig. 11). Rows of frus- 

 tules irregular, obsolete ; valves linear-lan- 

 ceolate, subulate, somewhat acute. Length 

 1-140". 



Three other species. 



BIBL. Kiitzing, Bacill. 10; id. Sp.Algar. 



RHAPHONEIS, Ehr. An ill-defined ge- 

 nus of Diatomaceae. 



Char. Frustules single, quadrangular, na- 

 vicular ; valves without a median aperture 

 (nodule ?); median sutural line longitudinal ! 

 Marine. 



Eleven species. 



BIBL. Ehrenberg, Ber. d. Berl. Akad. ; 

 1844. 74 ; Kutzing, Sp. Alg. 49. 



RHINOTRICHUM, Corda. A genus of 

 Mucedines (Hyphomycetous Fungi), grow- 

 ing upon dead wood, characterized by erect, 

 simple, or sparingly divided fertile filaments, 

 the last joint of which is clavate and covered 

 with minute spines, scattered or in trans- 

 verse rows, bearing single spores. Two (new) 

 British species are described by Berkeley 

 and Broome. 



BIBL. Corda, Icones Fung. i. fig. 232; 

 Fries, Summa Veg. p. 501; Berk, and Broome, 

 Ann. Nat. Hist. 2nd ser. vii. p. 177. pi. 7, 

 xiii. p. 462. pi. 16. 



RHIPIDOPHORA, Kiitz. A genus of 

 Diatomaceae. 



Char. Those of Licmophora, except that 

 the frustules are each furnished with a di- 

 stinct stipes ; but as this is not always the 

 case, the character is of little or no value. 

 Marine. 



