ALCYONELLA. 



[ 27 ] 



ALDERIA. 



of the ovule, in which case it is distinguished 

 by some botanists as the epispenn ; gene- 

 rally it is formed from the cell inside the 

 embryo-sac, the latter expanding to dis- 

 place the nucleus which becomes absorbed ; 

 such albumen is called endosperm. Some 

 seeds, such as those of the Nymphaeaceae, 

 Piperacae and others, have both endosperm 

 and episperm, i. e. albumen formed inside 

 and outside the embryo-sac. The term 

 perisperm is often (advantageously) substi- 

 tuted for albumen, which has "quite a different 

 signification in physiological chemistry. 



The albumen of seeds is examined by 

 means of fine sections. In the horny or 

 bony seeds, the application of solution of 

 potash or nitric acid is very serviceable in 

 ascertaining the true cellular structure. 



BIBL. Schleiden and Vb'gel, Nova Acta, 

 1838, xix. p. 52 (plates) ; Sachs, Botanik, 

 1874, p. 681; Henfrey, Bot. (Masters), 

 1878, p. 154. 



ALC YONEL'LA. A genus of _ fresh- 

 water Polyzoa (Bryozoa), belonging to 

 the order Hippocrepia and family Pluma- 

 tellidae. 



Char. Tubes branched, adherent to each 

 other by their sides ; orifices terminal ; ova 

 (statoblasts) presenting an outer ring, but 

 free from spines. 



Polypary (polypidom) incrusting, and 

 forming a sponge-like brown or greenish 

 mass, attached to submersed wooden posts 

 &c. 



A, stagnorum (fungosa), PL 41. fig. 3. 

 Polypary indefinite ; orifices of tubes entire, 

 and without a furrow. Rare. 



A. Benedeni. Polypary indefinite ; tubes 

 emarginate at the orifice, and furnished with 

 a longitudinal furrow. Rare. 



A.flabellum. Polypary fan-shaped ; tubes 

 prostrate, with a furrow. Rare. 



BIBL. Johnston, Brit. Zooph. p. 391 ; All- 

 man, Polyzoa (Ray Society), p. 86 ; Nitsche, 

 Mull. Archiv, 1868. 



ALCYONIDTIDy(Halcyonellea, Ehr., 

 Johnston). A family of marine Polyzoa 

 (Bryozoa) of the order Infundibulata, and 

 suborder Ctenostomata. 



Char. Polypary sponge-like, fleshy, of 

 irregular form; cells irregularly arranged, 

 immersed, with a contractile orifice ; no ex- 

 ternal ovarian capsules. Genera : 



Alcyonidium, Lamx. Erect; lobed or 

 simple ; cells pentagonal. 



Cycloum, Hass. Incrusting, covered 

 with imperforate papillae ; eggs in circular 

 clusters. 



Sarcochitum, Hass. Incrusting, covered 

 with perforate prominences in which the 

 cells are immersed; eggs scattered singly 

 throughout the polypidom. 



BIBL. See the Genera. 



ALCYONLD'IUM, Lamx. A genus of 

 Infundibulate Polyzoa (Bryozoa), of the 

 suborder Ctenostomata, and family Alcy- 

 onidiidae. 



Char. Erect, lobed, or simple ; cells im- 

 mersed, pentagonal. 



Nine British species ; they occur attached 

 to marine objects by a narrow base. 



A. gelatinosum. Lobed, lobes subcylin- 

 drical, surface smooth; attached by a nar- 

 row base. Deep water. 



A. hirsutum. Lobed, compressed, surface 

 papillar from partial protrusion of the 

 polype-cells. Common. 



A. parasiticum. Incrusting, earthy, sur- 

 face porous. 



BIBL. Johnston, Brit. Zooph. p. 358; 

 Gosse, Mar. Zool. ii ; Hassall, Ann. N. Hist. 

 vii. p. 370 ; Reid, ibid. xvi. p. 393 ; Hincks, 

 Polyzoa, 1880, p. 490. 



ALCYO'NIUM. A genus of Ccelente- 

 rata or Zoophytes, belonging to the order 

 Anthozca, and family Alcyonidse, 



Char. Polype-mass lobed or incrusting, 

 spongy, containing scattered calcareous 

 spicula. The skin (ectoderm) coriaceous, 

 marked with stellate spores ; interior gela- 

 tinous, netted with tubular fibres and per- 

 forated with longitudinal canals termina- 

 ting in the polype-cells, which are subcuta- 

 neous and scattered. Polypes exsertile. 

 Marine. 



A. digitatum (spicula, PL 41. fig. 28). 

 Commonly called 'dead man's toes or 

 fingers,' and cows' paps. Form of poly- 

 pidom variable, greyish -white or orange- 

 coloured, skin somewhat wrinkled, stud- 

 ded over with stellate pores, even with the 

 surface. 



Very common, so that on many parts of 

 the coast scarce a shell or stone can be 

 dredged from the deep that does not serve 

 as a support to one or more specimens. 



A. glomeratum. Colour deep red ; rare. 



BIBL. Johnston, Brit. Zooph. p. 174; 

 Gosse, Mar. Zool. ; Gray, Ann. N. Hist. 

 1869, v. p. 117. 



ALDE;RIA, Pritchard. A doubtful 



nus of animals discovered by Alder. 



The body of one species (PL 49. fig. 14) 

 consisted of a vase- or cup-form, expanded 

 at the top and furnished with numerous 

 pointed tentacles, abruptly thickened to- 



ge- 



