ASPLENIUM. 



[ 70 ] 



ASTASIiEA. 



dusium arising from the anastomosing brancli 

 of the vein. Veins parallel, anastomosing 

 here and there. 



VI. Woodwardia. Sori in a single row, 

 lunular or linear, parallel with the rib, im- 

 mersed ; indusium arising from the anasto- 

 mosing branch of the vein, flat, free within. 

 Anastomoses of the veins forming hexagonal 

 spots. 



BiBL. See FiLicACEiE. 



ASPLENIUM, Presl., Spleen-wort.— k 

 well-known genus of Aspleniea3 (Polypodte- 

 ous Ferns), containing a number of indi- 

 genous species. 



ASTASIA, Ehr.— A genus of Infusoria, of 

 the family Astasia^a. 



Char. Unattached, no eye-spot. Ehren- 

 berg adds, a longer or shorter tail. Du- 

 jardin says, with a flagelliform filament, 

 which is not expanded at the base, but arises 

 suddenly from the anterior part of the body, 

 or from a more or less deep notch in it. 



Dujardin forms an unnecessary genus, 

 Peranema, to contain those species in which 

 the filament arises from the gradually nar- 

 rowed anterior extremity of the body. 



1. A.hcematodes, E. (PI. 23. fig. 16). Fusi- 

 form, tail very short j at first green, then red; 

 length 1-380'". 



The flagelliform filament was absent in the 

 specimens represented in the figure. The 

 substance of the body was insoluble in cau- 

 stic potash, even when heated to boiling, 

 merely becoming swollen. It exhibited nu- 

 merous vacuoles, which in some of the or- 

 ganisms were filled with green grains of 

 chlorophylle. The colour arose from di- 

 stinct granules of pigment, scattered through 

 the colourless substance ; when treated with 

 solution of iodine and then sulphuric acid, 

 the AstasicB became spherical, and were co- 

 loured blue, bluish-green and purplish-blue, 

 the purple tint apparently indicating the pre- 

 sence of cellulose. It was, however, after- 

 wards found that these colours were produced 

 by the acid alone (see PI. 25. fig. 25). 



This curious organism colours the water of 

 ponds, &c. blood-red. 



2. A. limpida, D. (PI. 23. fig. 17). Fusi- 

 form, colourless; length 1-550". 



There are other species, but they are ill- 

 defined. A. nivalis, Shuttle worth, found in 

 red snow, would appear to be an active form 

 of Protococcus viivalis. 



BiBL. See AsTASi^.A; also Shuttleworth, 

 Biblioth. de Geneve, Feb. 1840. 



ASTASIiEA, Ehr.~A family of Infusoria. 



Char. Body of spontaneously variable 



form, mostly with one or more flagelliform fila- 

 ments. ( Insoluble in solution of caustic potash . ) 



This family corresponds nearly to the Eu- 

 glenia of Dujardin, who asserts the existence 

 of a contractile integument. The form of 

 the body is variable, sometimes becoming 

 spherical, at others cylindrical, fusiform, &c., 

 and exhibiting a head- or tail-like process, 

 or both. In two genera, Colacium and Di- 

 stigma, the presence of the filament is doubt- 

 ful. The Astasisea are distinguished from 

 the Amocbsea by the absence of the irregular 

 foot-like process sent out by the latter from 

 all parts of the body. 



The forms included under the family thus 

 characterized are still very imperfectly un- 

 derstood, and it is probable that some of 

 them, separated generically by Ehrenberg,are 

 only transitional conditions of others. Infu- 

 soria exactly resembling Astasia hamatodes 

 and Eucjlena viridis occur without the flagel- 

 liform filaments ; Euglena also occurs in a 

 resting form, surrounded by a gelatinous en- 

 velope, like Chlamidomonas, and undergoes 

 division into 4, 8, 16 or more new indivi- 

 duals in this state, so as to form irregular, 

 floating Algoid patches; the green bodies 

 make their escape from the gelatinous enve- 

 lopes vmder certain circumstances, just in the 

 same way as the zoospores escape from the 

 cells of the Confervoid Algse. This resting 

 form also exhibits another character, espe- 

 cially in winter ; the gelatinous envelope ac- 

 quires a firm dense membranous coat over 

 its periphery, like the resting spores of the 

 Confervoids, and in some cases this coat is 

 polygonal and marked with ridges, &c. It 

 is probable that the colour of the species is 

 not constant, since it seems to depend upon 

 similar substances to that of the Palmellacese, 

 which are known positively to change from 

 green to red, and vice versa, and even to fade 

 into an almost colourless state when kept in 

 the dark. These organisms still require much 

 careful examination, not of isolated speci- 

 mens, but by watching their developmental 

 history constantly for extended periods and 

 through difi^erent seasons. More is said on 

 this subject under Protococcus. 



The following table gives the genera of 

 Ehrenberg and Dujardin : — 



Attached Colacium, Ehr. 



Unattached. 

 No flagelliform filaments, 2 eye-spots Distigma, Ehr. 

 One flagelliform filament. 

 One eye-spot. 



With a tail-like process Euglena, Ehr. 



Without „ Amblyophis, Ehr. 



«T . f Astasia, Ehr. (& 



