ALTEUTHA. 



AMBER. 



ALTEUTHA, Baird. A genus of Ento- 

 mostraca, of the order Copepoda, and family 

 Cyclopidse. 



'Char. Body depressed; foot-jaws two 

 pairs, small and simple ; two strong falciform 

 appendages arising from the fifth segment of 

 the body. 



One species, A. depressa (PI. 14. fig. 3). 

 Eye red. Found in Berwick Bay, but not 

 common. 



BIBL. Baird, Ann. Nat. Hi$t. xvii. p. 416 ; 

 and Brit. Entomostr. p. 216. 



ALTICA. See HALTICA. 



ALUCITA. A genus of Lepidopterous 

 insects, of the family Alucitidse. 



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, excepting that the anterior 

 wings have two, and the posterior three lobes. 



BIBL. See INSECTS (Wings). 



ALUM. This well-known substance con- 

 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 octohedral 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 soda-alum, chrome- 

 alum, &c. The crystals exert no influence 

 upon polarized light. Common alum pos- 

 sesses but little microscopic interest. Its solu- 

 tion is usedin some of the preservative liquids. 



ALYSCUM, Duj. A genus of Infusoria, 

 of the family Enchelia, Duj. 



Char. Body ovoid-oblong, irregular ; sur- 

 rounded with radiating cilia, provided also 

 with a lateral bundle of long recurved con- 

 tractile cilia, by means of which it leaps 

 suddenly from one place to another. One 

 species. 



Alsaltans (P1.23. fig.8). Colourless, with 

 faint longitudinal furrows ; length 1-1260 to 

 1-1000". 



Found in infusion of hay, and river-water, 

 which have been kept. 



Dujardin remarks that it differs from 

 Enchelys nodulosa, Duj. (Pantotrichum En- 

 chelys, Ehr.) only in the presence of the 

 contractile cilia. 



BIBL. Dujardin, Infus. p. 391. 



ALYSSUM, Linn. A genus of Crucifera 

 (Flowering Plants), possessing elegant stel- 

 late hairs. See HAIRS, of plants. 



AMBER. This substance, found as a 

 mineral, but strongly resembling in appear- 

 ance various gum-resins, is the fossil resin of 

 one or more Coniferous trees belonging to a 

 vegetation now extinct. It is found in drops, 

 lamellae and stick-shaped pieces, the form 

 and condition depending probably on the 

 mode and situation of its exudation from the 

 trees. In many instances the fragments of 

 amber contain well-preserved remains of the 

 animals and plants which lived at the period 

 of its formation, these having been enclosed 

 by the fluid resin as it escaped from the tree, 

 in a manner which may be exactly compared 

 with our mode of preserving microscopic 

 objects in Canada balsam. Numerous insects, 

 Arachnida and other animals, with leaves, 

 twigs, fruits, even flowers of plants, have 

 been described and referred satisfactorily to 

 their systematic position, and the aid of the 

 microscope has been largely called in for this 

 purpose, since the elementary structures are 

 in many cases perfectly preserved. The 

 tissue of the fragments of Coniferous wood, 

 the stomates of leaves, glandular and other 

 hairs have been recognized ; and besides the 

 larger Cryptogams, Mosses, Jungermanniae, 

 &c., peculiar microscopic Fungi and Diato- 

 macese have been preserved in a perfectly 

 distinct condition. 



The structure of the wood of the Amber- 

 fir, Pinites succinifer, Goppert, approaches 

 closely that of our Pinus Abies and P. Picea, 

 differing scarcely in any respect but in the 

 smaller number of the bordered pores, 

 which are of slightly different form. 



Three microscopic Fungi preserved in 

 amber have been described and figured by 

 Mr. Berkeley : 1. Penicillium curtipes ; 

 2. Brachycladium Thomasinum, and 3. 

 Streptothrix spiralis, all from the Baltic 

 coast. 



Ehrenberg has detected a number of fossil 

 Infusoria in amber, namely, Amphora gracilis, 

 Cocconeis borealis, Cocconema Cistula, Fra- 

 gilaria Capurina, Navicula afnis, N. 

 Amphioxys, N. Bacillum, Pinnularia capitata, 

 P. Gastrum. 



BIBL. Goppert and l&erendt, Die Bernstein, 

 Sfc., Berlin, 1845; analysis of ditto in Reg ens- 

 burg Flora, vol. xxviii. p. 545, 1845; Ehren- 

 berg, Bericht. Berlin. Acad. 1848. p. 17; 

 Berkeley, on Moulds detected in Amber, 

 Annals of Nat. Hist. 2nd ser. vol. ii. p. 380. 

 tab. xi., xii. 



