ALSOPHILA. 



ALYCUS. 



The three British species may be thus 

 distinguished : 



, /Shell reticulated reticulata*. 



*' \8hellstriatedorgrooved 2. 



( Anterior margin of shell nearly 



2 ) straight, shell brown quadrangularis\ . 



j Anterior margin of shell convex, 



( shell colourless ovata. 



PI. 19. fig. 4. 



PI. 19. fig. 5. 



131, 



Alsophila excelsa. 

 Pinnule with son". 



BIBL. Baird, Brit. Eiitomost. p. 

 pi. 16. 



ALSOPH'ILA, B. Fig. 8. 



Brown. A genus of 

 PolypodiaceousFerns. 

 Exotic (fig. 8). 



Char. Sori globose, 

 dorsal, on a vein or in 

 the fork of a vein. 

 Receptacle mostly 

 elevated, often vil- 

 lous. Involucre ab- 

 sent. Veins simple 

 or furcate, free. 



Arborescent, mostly tropical; species 

 numerous. 



Sections of their petioles exhibit fine scala- 

 riform ducts, the slits between the fibres 

 forming many perpendicular rows. 



BIBL. Hooker & Baker, Syn. Filic.p. 31. 



ALTERNA'RIA, Nees. A 

 genus of Torulacei (Coniomyce- Fig. 9. 

 tous Fungi). Microscopic fila- 

 mentous Fungi, remarkable for 

 their flask-shaped, cellular spores, 

 produced in chains which ulti- 

 mately break up into the single 

 links (fig. 9). 



A. tennis grows parasitically 

 upon other filamentous Fungi, 

 and on decaying gourds, and is 

 common about Berlin, Prague, 

 and other places. Corda made ^ 

 the ripe spores germinate on Cla- 

 dosporium lierbarum kept moist. 

 They usually first protruded a 

 filament from the neck or atte- 

 nuated projection, and afterwards 

 others from the cells at the sides 

 and opposite end of the spore. Alternaria 

 These filaments became branched. Fertile 



The Messrs. Tulasue have spore-bear- 

 shown that Alternaria tennis is j,^? th reads 

 merely a state of the common ma | n ifled). 

 Sphceria herbarum. 



BIBL. Corda, Ic. Fung. iii. p. 5, pi. 1. 

 fig. 16; Prachtfl. europ. Schimmelbild. p. 13; 

 Tulasne, Fung. Carpologia, ii. pi. 32. 



ALTERNATION OF GENERATIONS. 

 See GENERATIONS. 



ALTEUTHA, Baird (Peltidium, Brady). 

 A genus of marine Entomostraca, of the 

 order Copepoda, and family Cyclopidae. 



A. depressa (PI. 19. fig. 3). Eye red. 

 Found in Berwick Bay, but not common. 



A. interrupta, common ; A. crenatula. 



BIBL. Baird, Brit. Entom. p. 216; Brady, 

 Copepoda (Ray &>c.), ii. p. 158. 



AL'TICA. See HALTICA. 



ALU'CITA. A genus of Lepidopterous 

 insects, of the family Alucitidae. 



The species are remarkable from having 

 the wings divided into six lobes or rays 

 which are fringed with long narrow scales 

 resembling hairs, giving them a beautiful 

 feathery appearance. They are not uncom- 

 mon in'gardens, and sometimes enter out- 

 houses. 



The species of Pterophorus exhibit the 

 same structure, except that the anterior 

 wings have two, and the posterior three lobes. 



BIBL. See INSECTS (Wings). 



ALUM. This well-known substancecon- 

 sists chemically of potash and alumina, with 

 sulphuric acid and water. Its crystals belong 

 to the regular cubic or tesseral system, and 

 usually assume the octahedral form. When 

 dissolved in boiling water with slaked lime, 

 it crystallizes in cubes. The term alum has 

 recently been extended to those compounds 

 in which the potash is replaced by other 

 bases ; thus we have ammonia-alum, 

 chrome-alum, &c. The crystals exert no 

 influence upon polarized light. Common 

 alum possesses but little microscopic 

 interest. Its solution is used in some of 

 the preservative liquids. 



AL VEOLINA, D'Orb. A genus of Fora- 

 miniferalmperforata,of the family Miliolida 

 (Carpenter), nearly allied to Orbiculina, but 

 elongated in the direction of the axis ; Or- 

 biculina being greatly compressed in this di- 

 rection. Alveolma rotella (D'Orb., sp.), how- 

 ever, is nautiloid ; AL melo, var. a, Ficlit. 

 and Moll, is oblately spheroidal ; var. ft, 

 prolately spheroidal; AL ovoidea, D.'Orb., 

 elongate-oval ; AL sahilosa, Montft., fusi- 

 form ; and AL elongata, D'Orb., is sub- 

 cylindrical. 



A. fmiformis (pi. 23. fig. 15) ; A. rotella 

 (pi. 23. fig. 16). 



BIBL. Carpenter, Phil. Trans. 1850, p. 

 552 ; Foram. p. 99 ; Parker and Jones, 

 Ann. Nat. Hist. ser. 3. viii. p. 161. 



AL'YCUS, Koch. A genus of Acarina, 

 fam. Trombidina. 



