ACTINOPTYCHUS. 



ACTINURU& 



greenish ; rays shorter than the body ; 

 diam. 1-280" to 1-620"; fr. water. Per- 

 haps A. sol coloured by chlorophyll. 



A. diyitata, D. Colourless, depressed, 

 tentacles flexible, thickened at base, and 

 when contracted forming finger-like pro- 

 longations ; diam. 1-770"; fr. water. 



A. (jranata, D. Spherical; opaque in 

 centre; rays taper, shorter than body; 

 fr. water. 



A. paradoxa, Carter (PL 61. fig. 13). 

 With numerous capitate and longer simple 

 tentacles; fr. water. Bombay. 



A. oculata, St. = A. sol? A. discus, D. 

 Trichodiscus sol, E. (PI. 32. fig. 8). A. pe- 

 dicellata, D Podophrya fixa, E. A. stella, 

 Perty = the eggs of one of the Rotatoria. 



The manner in which these animals feed 

 is curious. Any part of the surface of the 

 body may be converted into a temporary 

 stomach. When an infusorium or a minute 

 alga comes into contact with one of the 

 tentacles, it generally becomes adherent. 

 The tentacle with the prey then slowly 

 shortens, and the surrounding tentacles ap- 

 ply themselves upon it, bending their points 

 around the captive, so that it gradually be- 

 comes enclosed on all sides. In this way 

 the prey is gradually brought to the surface 

 of the body, The spot at the surface of the 

 bodv upon which the captured organism is 

 lying slowly retracts, and forms at tirst a 

 shallow depression, which gradually becomes 

 deeper and deeper, in which the organism is 

 finally lodged. As the depression becomes 

 still deeper, its edges coalesce, and thus a 

 cavity closed on all sides is formed, in which 

 it remains for a certain time and becomes 

 digested. If there be any indigestible resi- 

 due, a passage for its exit is formed, and it 

 is expelled by further contractions of the 

 substance of the body, and in the same or a 

 different direction from that at which it 

 entered, the canal and the aperture entirely 

 disappearing. 



BIBL. Kolliker, Zeifschr. f. ivissens. Zool. 

 Bd. i. (Qt. Micr. Jn. i.) ; Stein, Archiv f. 

 Naturyesch. 1849 ; Brightwell, In/us, of 

 Norfolk ; Pritchard, Infus. ; Carter, Ann. 

 N. Hist. 1864 ; Claparede and Lachmann, 

 Etudes ; Pertv. Z. Kenntniss fyc. p. 159. 



ACTINOPTYCHUS, Ehr. A genus of 

 Diatomacese. (Cohort Coscinodisceae.) 



Char. Frustules solitary, free, disk-shaped, 

 with rays and internal radiating septa; 

 valves apparently cellular (areolar), except 

 opposite the rays. 



The presence of true internal septa is 



doubtful; hence it becomes a question 

 whether this genus should not be consoli- 

 dated with Actinocyclus. 



Kiitzing enumerates 16 species, distin- 

 guished principally by the number of septa 

 and rays ; A. temarius, septa 3 ; A. quater- 

 narius, septa 4 ; A. senarius, rays 6 (PL 25. 

 fig'. 16), &c. A. hexapterus, with 6 thick, 

 solid conical rays, is one of the calcareous 

 corpuscles of an echinoderni ; the margin of 

 the disk thick, undulate, and toothed within. 

 Many of the species are fossil. 



BIBL. Ehrenberg, Infus. Abh. d. Berl. 

 Akad. 1838, and Berl. Bericht. 1844 ; Kiitz- 

 ing, Bacill. 134; Sp. Alg. 130; Greville, 

 Micr. Trans. 1866, p. 5 ; Rabenhorst, Alg. 

 p. 35. 



ACTINOSPH^'RA, Perty.-A doubt- 

 ful genus of Rhizopoda. 



Char. Body minute, spherical, surrounded 

 with irregular, rather rigid processes. Move- 

 ment that of swimming on various axes. 



Processes stout and taper. Body colour- 

 less, containing greyish-green (food-) spots. 



BIBL. Perty, Zur Kenntniss fyc. p.189. 



ACTINOSPH^E'RIUM = Actinophnjs, 

 in part. 



ACTINOTHYR'IUM,Kunze. A genus 

 of Sphseronemei (Stylosporous Fungi), 

 forming minute round, Fig. 4. 



flat, black spots, with a 

 central boss of close, 

 radiatingjfibrous struc- 

 ture. British species: 



A. yraminis, Kunze. 

 On leaves and stalks of 



Grasses in spring (fig. Actinothyriumgraminis 



4). The innate, radi- 0"ghl y magnified), 

 ately fibrous, shield-like perithecium finally 

 dissolves at the apex. The stylospores, 

 which are spindle-shaped, are formed be- 

 neath the disk, attached by their bases; 

 Fries conjectures that they are transformed 

 asci. 



It is probably a state of some Sphceria or 

 allied genus. 



BIBL. Greville, Crypt. Flora, t. 218. 



ACTINOT'RICHA, Kent. A genus of 

 Infusoria, fam. Oxy trichina. 



ACTINU'RUS. A genus of Kotatoria, 

 of the family Philodinaea, Ehr. 



Char. Eye-spots two, frontal (red) ; tail- 

 like foot with 2 lateral horny processes and 

 3 terminal toes. (Rotifer with 5 points to 

 the foot.) 



Agrees with Rotifer in general structure ; 

 teeth 2 in each jaw (PL 43. fig. 2). 



1 species, A. Neptunius (PL 43. fig. 1). 



