ALCYONELLA. 



[ 23 ] 



ALG.E. 



the almond, nut, &c., are examples of fleshy 

 cells containing abundance of oil-globules. 



The albumen of seeds may be formed by 

 the development of the tissue of the nucleus 

 of the ovule, in which case it is distinguished 

 by some botanists as the episperm; some- 

 times it is formed from the cells inside the 

 embryo-sac, the latter expanding to displace 

 the nucleus which becomes absorbed; such 

 albumen is called endosperm. Some seeds, 

 such as those of the Nymphaeacese, Ranun- 

 culaceae 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 ascertain- 

 ing the true cellular structure. 



BIBL. Schleiden and Vogel, Ueber Albu- 

 men, Nova Acta, 1838, xix. p. 52 (with 

 plates). 



ALCYONELLA. A genus of freshwater 

 Zoophytes or Polypes, belonging to the 

 order Bryozoa (Polyzoa). 



Char. Polypidom fixed, incrusting or 

 floating in the form of an irregular sponge- 

 like mass composed of vertical aggregated 

 membranous tubes opening on the surface. 

 Polypes ascidian, the mouth encircled with 

 a single series of filiform tentacles, depressed 

 or incomplete on one side : eggs coriaceous, 

 smooth. 



1 species, Al. stagnorum, PI. 33. fig. 3., found 

 in autumn in stagnant waters, especially those 

 tinctured with iron in solution ; the polypi- 

 dom forms large, blackish-green, amorphous 

 masses. The tentacles are sometimes disposed 

 circularly. The ova are figured in PI. 33. fig. 4. 



BIBL. Johnston, Brit. Zoophytes, 1847. 



ALCYONIUM. A genus of marine Po- 

 lypes or Zoophytes, belonging to the order 

 Anthozoa and family Alcyonidae. 



Char. Polype-mass lobed or incrusting, 

 spongious, the skin coriaceous, marked with 

 stellate pores ; interior gelatinous, netted 

 with tubular fibres and perforated with lon- 

 gitudinal canals terminating in the polype- 

 cells, which are subcutaneous and scattered. 

 Polypes exsertile. 2 species : 



A . diyitatum. Form of polypidom variable, 

 greyish-white or orange-coloured, skin some- 

 what wrinkled, studded 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. Zoophytes. 



ALDERIA. A name proposed by Mr. 

 Pritchard to designate a new genus of animals 

 discovered by Mr. Alder. 



The body of one species (P1.40. fig. 13) con- 

 sisted of a vase- or cup-form, expanded at the 

 top and furnished with numerous pointed 

 tentacles, abruptly thickened towards the 

 base and forming more than one row : they 

 had very little motion, but were occasionally 

 bent forwards, and the whole were sometimes 

 slowly retracted. The body was attached to 

 a Sertularia by a tolerably stout stem. 



A second species (P1.40. fig. 14) was rather 

 smaller, the body of an ovate form with a 

 very slender and shortish stem; the tentacles 

 were capitate, not so numerous as in the first 

 species, and placed in a single row round a 

 narrow disc. 



This species was also found on a Sertularia. 



A third (PI. 40. fig. 15) was found in fresh 

 water. Its body was pear-shaped, or rather 

 bell-shaped, with a distinct rim round the 

 top and a single row of delicate capitate 

 retractile tentacles ; the stem was long and 

 slender. Mr. Alder remarks that they come 

 nearest to the genus Acineta of Ehrenberg ; 

 the third species somewhat resembles Ac. 

 mystacina, E., yet differs from it in the latter 

 appearing of a more simple form, and the 

 tentacles arising irregularly from different 

 parts of the body. 



Mr. Alder remarks that they form a more 

 perfect link between the Infusoria and the 

 Campanularian Zoophytes than any hitherto 

 known. 



Should these animals be again met with, 

 it would be very desirable to keep them 

 alive and ascertain whether they do not 

 represent an immature condition of some 

 Zoophytes. They appear to us to have but 

 little affinity with those species of Acineta, 

 the existence of which as mature organisms 

 has not been called in question. 



BIBL. Trans, of Tyneside Naturalists' 

 Field Club, i. p. 365 ; Ann. Nat. Hist. vii. 

 p. 426 ; Pritchard's Inf. Anim. p. 558. 



ALECTORIA, Acharius. A genus of 

 Parmeliaceous Lichens, in eluding two British 

 species, A. jubata and A. sarmentosa, the 

 fructification of which is rarely met with. 



ALG^E, Sea-weeds, ^c. This class of the 

 Thallophytes includes the Sea-weeds and the 

 multifarious green vegetable forms of simple 



