AECELLINA. 



[ "1 ] 



ARCYRIA. 



A. arenaria \ in sand, under moss and 

 lichens. Otiier species. 



BiBL. Elirenberg, Infus. ; Chiparede 

 and Lacliniann, Infiis. p. 444 ; Biitsclili, 

 Schultzes Arch. xn. 459 (pi.). 



ARCELLl'NA, Elir.— A family of Lo- 

 bose Rhizopoda. 



Cltar, Animals contained in a univalve 

 membranous or solid inflexible carapace, 

 of an urceolate or shield-like form, with a 

 sinp-le orifice from which one or more irre- 

 gular and variable expansions are protruded, 

 which form the organs of locomotion. 



Biitschli describes conjugation ; but the 

 result is doubtful. 



The substance of the body resembles that 

 of an Amoeba. Gen, : — 



Shell flexible, dorsal... Pseudochlamys. 



Shell flexible, universal Ampkizonella. 



Shell solid, inflexible. 



Not incrnsted with foreign matters. Arcella. 

 Incrusted with agglutinated fo- 

 reign matters. 



With tubular prolongations Echinopyxis. 



Without tubular prolongations... Difflugia. 



ARCH^DIS'CUS, Brady.— A small, 

 lenticular, asymmetrical, hyaline Fora- 

 miuifer, of the Nummuline type ; found in 

 the Carbonifei'ous Limestone. 



BiBL. Bradv, Ann. N. H. 1873, xii. 286. 



ARCHEGd'NIUM. Also called ;j2s<«7/«- 

 dium. — The rudimentary organ representing 

 the ovule in the higher Flowerless Plants, 

 such as Mosses, Ferns, &c. (excluding the 

 Thallophytes). These organs are more mi- 

 nutely described under the heads of the 

 various Classes, in speaking of their repro- 

 duction. 



In the Mosses and Liverworts they are 

 flask-like cellular bodies, found in terminal 



Fig. 30. 



Fig. 31. 



Archegonia of ^VTosses. 

 Magnified 50 diameters. 



or axillary buds on the leafy stems (figs. 30 

 & 31). In the Ferns and Equiseta they are 

 produced on the prothallium, after the ger- 



mination of the spores. In the Lycopodi- 

 ace;e and Marsileacepe they are produced 

 upon the cellular plate, representing a pro- 

 thallium, developed in the large spores when 

 these begin to germinate. The corpusctda of 

 the Ooniferse are analogous bodies to the last. 



SeeHEPATICACE..E,MuSCACE^,FlLICACE^, 

 EQUISETACEiE, LYCOPODIACEiE, MaRSILE- 



ACEJE ; also Conifer.^ and Ch.a.iiace.e. 



ARCHID'IUM,Bridel.— Ag•enusofPhas- 

 cace^e(Acrocal'pousMosses), of which but one 

 species is found in Europe (A. j}/iascoides= 

 Phascum alternifoUum, Hook, and T. ), grow- 

 ing upon banks and fallow ground, on clay 

 or chalky soil. It is remarkable for the 

 sessile globular capsule, without a trace of 

 an operculum, the columella soon oblite- 

 rated, and the spores being few in number, 

 very large and angular in form (figs. 32 & 



Fig. 82. 



Fig. 33. 



Archidium. 



Open capsules devoid of columella and with large 



spores. Magnified -10 diameters. 



33). The calyptra is torn away in the mid- 

 dle during the expansion of the capsule, as in 

 Sj)/>af/tium, leaving a short tumid vaginula. 



BiBL. Wilson, Bn/ol. Brit. p. 24. 



ARCTO'A, Br. and Sch. = lJicRAXTJM. 



ARCYRTA, Hill.— A genus of Myxo- 

 mycetes, growing on rotten wood, with fre- 

 quently bright-coloured spores and fila- 

 ments. The elastic filaments of the capil- 

 litium have no spiral fibres, but are a little 

 tuberculated. The species in general are 

 not confined to Europe or the United States, 

 but have a very wide geographical range, 

 occurring in tropical and subtropical dis- 

 tricts as well as in those which ai'e tem- 

 perate. Species : — 



A. punicea, Pers. Common ; spores and 

 capillitium purpli.sli vermilion. A dark form 

 is separated by Rostafinski as A. ferru~ 

 ginea. Grev. Sc. Crypt, Fl. t. 130. 



A. incarnate^ Pers. Not uncommon ; 

 smaller, with a shorter stipes and with flesh- 

 coloured spores and capillitium. 



A. cinerea, Bull. Spores and capillitium 

 cinereous. 



A, nutans, Bull. Spores and capillitium 

 dirty-yellow ; capillitiiun nodding. Trichia 



