ARCELL1NA. 



ARCYRIA. 



A. arenan'a- in sand, under moss and 

 lichens. Other species. 



BIBL. Ehrenberg, In/us. ; Claparede 

 and Lachmann, In/us, p. 444; Biitschli, 

 Schultze's Arch. xii. 459 (pi.). 



ARCELLI'NA, Ehr. A family of Lo- 

 bose Rhizopoda. 



Char. Animals contained in a univalve 

 membranous or solid inflexible carapace, 

 of an urceolate or shield-like form, with a 

 single 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 Amphizoiiella. 



Shell solid, inflexible. 



Not incrusted with foreign matters. Arcella. 

 Incrusted with agglutinated fo- 

 reign matters. 



With tubular prolongations Echinopyxis. 



Without tubular prolongations. . . Difflugia. 



ARCILEDIS'CUS, Brady. A small, 

 lenticular, asymmetrical, hyaline Fora- 

 minifer, of the Nummuline type ; found in 

 the Carboniferous Limestone. 



BIBL. Brady, Ann. N. H. 1873, xii. 286. 



ARCHEGO'NIUM. Also called pistilli- 

 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. 81. 



Archeeonia of Mosses. 

 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- 



miDation of the spores. In the Lycopodi- 

 aceae and MaisHeaceae they are produced 

 upon the cellular plate, representing a pro- 

 thallium, developed in the large spores when 

 these begin to germinate. The corpuscula of 

 theConiferse are analogous bodies to the last. 



EQUISETACE^E, LYCOPODIACE^E, MARSILE- 

 ACE^ ; also CONIFERS and CHARACEJE. 



ARCHID'IUM,Bridel. AgenusofPhas- 

 caceae(AcrocarpousMosses), of which but one 

 species is found in Europe (A. phascoides= 

 Phascum alternifolium, 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. 32. 



Fig. 33. 



Archidium. 



Open capsules devoid of columella and with large 

 spores. Magnified 40 diameters. 



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

 dle during the expansion of the capsule, as in 

 Sphagnum, leaving a short tumid vaginula. 



BIBL. Wilson, Bryol. Brit. p. 24. 



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



ARCYR'IA, 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- 

 litiurn 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 are tem- 

 perate. Species : 



A. punicea, Pers. Common j spores and 

 capillitium purplish vermilion. A dark form 

 is separated by Rostafinski as A. ferru- 

 ginea. Grev. So. Crypt. Fl. t. 130. 



A. incarnata, 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 ; capillitium nodding. Tiichia 



