AETOBATES. 



AGAMA. 



AETO'BATES, a genus of fossil fishes allied to the Rays. The 

 species are found in the London clay of Sheppey. (Agassiz.) 



AGALLOCHUM. [EXCA:CARIA ; AQUILARIACE.E.] 



AGALMATOLITE (also Pagodite, Bildsldn, Lardlte). This mineral is 

 found in China, and is seldom brought into this country except cut 

 into various figures. Less characteristic varieties have been found in 

 Transylvania and Saxony ; it is found also in Wales. Occurs massive. 

 Fracture coarae splintery, imperfectly slaty. Soft. Colour white, 

 with a shade of gray, green, yellow, red, or brown, none of them 

 bright. Streak shining. Unctuous to the touch. Slightly trans- 

 lucent, but in most cases only the edges. Specific gravity 2'815. 



Before the blowpipe infusible, but becomes white. Partly soluble 

 in sulphuric acid, leaving a residue, chiefly of silica. 



Analysis of the Chinese variety by Vauquelin : 



Silica 



Alumina 



Lime 



Protoxide of Iron . 



Potash 



Water . 



56 

 29 

 2 

 1 

 7 

 5 



100 



A'GAMA, in Zoology, a genus of reptiles belonging to the order 

 Saurians, and family Jyuaniam, of Baron Cuvier. 



Iii the form of their heads and teeth the species of Agama resemble 

 the common lizards, but differ in the imbricated scales which cover 

 their tails. These animals have the body thick, and shorter in pro- 

 portion than the generality of the saurian family ; the skin is lax, 

 and capable of being distended or puffed out with air at the will of 

 the reptile ; the whole body, as well as the head, neck, and feet, is 

 covered with minute rhomboidal or hexagonal scales, often prolonged 

 in the form of little spines, and bristling when the body is inflated 

 with air. The head is short, broad, and flat, particularly towards the 

 occiput ; the neck also is short, and the tail seldom longer than the 

 body. These proportions give the Agamas much of the hideous and 

 disgusting appearance of toads. In many parts of South America 

 they are called Chameleons, from their power of dilating the skin 

 with air, and imitating, to a certain extent, those animals in the 

 various hues which they are capable of assuming. In other respects 

 the various species of Agamas differ so considerably from one another, 

 as to have induced Baron Cuvier to arrange them in separate sub- 

 genera, distinguished by the form of their scales and the presence 

 or absence of pores in the thighs. Generally speaking, the Agamas 

 have no thigh pores ; some however are provided, as is the case with 

 many other saurian reptiles, with a row of these pores along the inner 

 surface of each thigh ; some species have the toes so short and rigid 

 as to compel them to live entirely on the surface of the earth, where 

 they reside among rocks and heaps of stone, and conceal themselves 

 in the crevices; others again, which have long and flexible toes, ascend 

 trees with great facility, and sport among their branches with the 

 utmost security. All are of a diminutive size, and, like most other 

 reptiles, feed upon insects and other small animals : one or two 

 species however are reported to be herbivorous. Their geogra- 

 phical distribution is very extensive, and embraces all the hot and 

 most of the temperate parts of the known world : Asia, Africa, 

 Australia, and South America have each their appropriate species, 

 which often differ from one another very slightly. 



The most remarkable species are, of those without pores on the 

 interior face of the thighs : The Muricated Agama (Agama muricata, 

 Cuvier), first described by the celebrated John Hunter in the 

 zoological part of White's ' Voyage to New South Wales.' It is 

 one of the moot common lizards of that colony ; measures upwards 

 of a foot in length, comprehending the tail, which is twice as long as 

 the body, and, from the great length and perfect division of its toes, 

 readily ascends trees, and lives entirely in the woods, where it hunts 

 about for insects and caterpillars. Its general colour is a brownish 

 gray, marked with dusky bars, which run in a longitudinal direction 

 on the body, but transversely on the legs and tail. The scales which 

 cover the upper and outer parts of the trunk and extremities are 

 rhomboidal and carinated, or elevated into sharp-pointed ridges, 

 forming parallel lines or rows of spines upon the back and sides, 

 from the shoulders to the very point of the tail. The head is covered 

 with similar scales, all directed backwards and prolonged upon the 

 occiput into a crest of weak spines. The toes of all the feet are well 

 separated, and furnished underneath with small pointed scales ; the 

 two middle toes of the hind feet are nearly twice the length of the 

 others. 



The Agama, barbata of Cuvier is another species from the same 

 I - ;. 1 ity. It is rather larger than the Muricated Agama, but preserves 

 the same relative dimensions, and lives in the forests in the eamc 

 manner. This species is figured and described in White's 'Voyage,' 

 p. 255, but wag considered by Mr. Hunter as a mere variety of the 

 former. 



i itlier species of this division, having pores on the inner surface of 

 the thighs, are the Leiolepit (A. guttata of M. Cuvier) of Cochin- 

 China, with white rays and spots on a bright blue ground ; the 

 Trnpidolepu (A. undulata), of a uniform dark blue colour with a 



white cross on the throat, and which, as well as the kindred specie?, 

 .1. niyi-i-collaris and A. cyclurus, described by Spix, inhabits various 



parts of South America; the Bracht/loplics (A. ifttata), which seems 

 to form the connecting link between this genus and the guanas, from 

 which latter it is distinguished only by the absence of teeth in the 

 palate ; it is found in India, and has light blue Bands upon a dark 

 blue ground: and lastly the Plujsiynuilt^s (A. cocincimts), from the 

 Malayan Peninsula, remarkable for its large size, uniform blue 

 colour, but more particularly from being one of the very few 

 species of saurian reptiles which feed upon vegetable substances. 

 Baron Cuvier assures us that it lives entirely upon fruits and nuts. 



Of the Agamas without pores in the thighs, the principal species are, 

 the Spiuous Agama (A. acideata) of a yellowish gray colour with 

 numerous transverse brown bands. All the upper parts of the body 

 are covered with elevated scales, forming small pointed pyramids of 

 four-sides ; the body is short and thick, the tail likewise short, the 

 head broad and flat, and the belly protuberant. Excepting in the 

 length of the tail, and the body being covered with scales, the whole 

 animal has much of the form and appearance of a frog or toad : it is 

 found at the Cape of Good Hope, and is of larger size than the 

 generality of the other species. 



Spinous Agama (At/ama aculcata). 



The Tapayaxin (A. orblmlaris) of South America is very similar 

 to the species last described in its form and proportions, but is 

 still shorter and thicker. The extraordinary figure of this reptile, 



