EYLAIS. 



[ 256 ] 



FAVELLIDIUM. 



EYLAIS, Latr. A genus of Arachnida, 

 of the order Acarina, and family Hydrach- 

 nea. 



Char. Palpi longish, fourth joint longest, 

 the fifth obtuse, somewhat tumid, spinous ; 

 mandibles imguiculate ; rostrum very short, 

 mouth round ; body depressed ; two approxi- 

 mate pairs of eyes ; coxae comparatively nar- 

 row, the fourth only in contact with the third 

 at its base. 



E. extendens (PI. 2. fig. 28). Skin soft, 

 furrowed, with the ramified alimentary canal 

 visible through its substance. Between the 

 two anterior coxae (d) is seen the bilobed 

 labium (a), the posterior portion containing 

 the round and ciliated mouth, the anterior 

 portion forming a kind of hood; palpi (b) 

 with the three first joints very short; mandible 

 consisting of a long thick joint, with a thick 

 mobile claw (c). Fig. 28 d, under surface of 

 body, exhibiting from before backwards: 

 the mouth, with the hood, and the palpi; 

 next two groups of anterior coxae ; the vulva 

 and two stigmata ; the four posterior coxae ; 

 and lastly, the anus in the middle, with a 

 stigma on each side. 



The larvae are hexapod, reddish, pellucid, 

 with the eyes four, wide apart. 



BIBL. Duges, Ann. des Sc. not. 2 ser. i. 

 p. 156; Gervais, Walcken. Arachnid, iii. 

 p. 207 ; Koch, Deutschl. Crustac. 



F. 



FADYENIA, Hook. A genus of Nephro- 

 dieae (Polypodaeous Ferns). Exotic. 



FAECES. We shall not dwell upon the 

 nature of the objects contained in the foeces; 

 suffice it to say, that they may consist of, 

 the elements of the various secretions poured 

 into the intestinal canal; the products of 

 inflammation; undigested remains of arti- 

 cles of food, or bodies taken with the food 

 or drink ; and entozoa. Some of these re- 

 semble others very closely to the naked eye. 

 The use of chemical reagents should never 

 be omitted in their examination. 



BIBL. See CHEMISTRY, Animal. 



FASCIAE. The fasciae consist of the same 

 elements as AREOLAR TISSUE, and present 

 all the varieties of arrangement intermediate 

 between it and TENDON. 



FATTY DEGENERATION. See DE- 

 GENERATION, FATTY. 



FATTY TISSUE, or ADIPOSE TISSUE. 

 This is formed of colourless cells, with a 

 very delicate, transparent, structureless cell- 



wall, enclosing, in the normal state, globules 

 of yellowish fat (PL 40. fig. 41). The cells 

 generally occur in groups, surrounded by or 

 imbedded in areolar tissue. They are rounded 

 when isolated, or polygonal when aggregated, 

 and from 1-800 to 1-300" in diameter; and 

 the fat so fills them, that neither the nucleus 

 which they contain, nor the cell-wall, is visi- 

 ble. The fat may be removed by drying 

 them, and digesting with aether, when the 

 cells appear contracted and wrinkled. In 

 emaciated and dropsical subjects, each cell 

 contains a number of small globules of fat, 

 frequently of a reddish colour (PI. 30. fig. 3), 

 together with serum, and the nucleus is very 

 distinct. Sometimes in these cases the cells 

 are somewhat spindle-shaped or stellate. 

 The fat contained in the cells is ordinarily in 

 a liquid state, but sometimes the margarine 

 separates in the crystalline form (PI. /. fig. 

 16 a). 



In the mammalia generally the fatty tissue 

 occurs in the same localities, and has the 

 same structure as in man. In fishes, the fatty 

 matter is deposited principally in the liver. 

 In reptiles, it occurs chiefly in the abdomen; 

 thus in the frog and toad it forms long ap- 

 pendages occupying the sides of the spine. 

 In birds, it exists chiefly between the peri- 

 toneum and the abdominal muscles, and in 

 some of the bones. In many of the lower 

 animals it appears to exist in the state of 

 solution only. 



Fatty matter maybe deposited in cells of all 

 kinds, as in FATTY DEGENERATION. During 

 the development of cells, it exists in solu- 

 tion. The action of solution of potash is 

 often of service in distinguishing globules of 

 sarcode, which have a high refractive power, 

 and much resemble those of fat from this 

 substance, as it dissolves the former, but not 

 the latter. 



BIBL. Todd and Bowman, Phys. of Man', 

 Kolliker, Mikroskop. Anat. 1. 



FAVELLA. A form of the conceptacular 

 fruit of the Florideous Algae, where the 

 spores are collected in spherical masses, si- 

 tuated wholly upon the external surface of 

 the frond, as in Ceramium and Callitham- 

 nion. 



FAVELLIDIUM. A form of the concep- 

 tacular fruit of the Florideous Algae, when 

 the spores are collected in spherical masses, 

 attached to the wall of the frond or imbedded 

 in its substance, as in Halymenia and Du- 

 montia. The term is usually extended to 

 similar fruits not perfectly immersed, e. g. 

 those of Gigartina, Gelidium, &c., where 



