GECKOTIDJE. 



GECKOTlD.fi. 



939 



lateral edges. Feet strong; pincers large, cylindrical, tuberculous, 

 and touching throughout their length ; anterior edge of the arms 

 nodulous ; succeeding feet dentilated on the edges, those of the third 

 pair the longest. Six rows of dentations on the tarsi. Colour 

 brownish-red. Length rather more than three inches. (Milne- 

 Edwards.) 



It is found iu Brazil. 



Gecarcinue. Carapace not much elevated, but very convex on the 

 sides. Front very strongly curved below. Orbits deep, inclining to 

 oval, and without a notch on the external side. Internal antenna; 

 nearly hidden under the front, which has a small prolongation that 

 goes to join the epistome. The disposition of the external antenna; 

 and that of the canthus of the orbit nearly the same as in the preceding 

 genus. Buccal frame nearly circular, and not clearly separated from 

 the pterygostomian region?. External jaw-feet very wide, but with a 

 space between them ; their second joint completely covers the suc- 

 ceeding joints, which are inserted on its internal surface. The external 

 appendage of these organs is hidden under their second joint, and its 

 extremity scarcely overpasses it. Feet presenting nothing remarkable, 

 excepting that their edges are armed with spiniforni teeth. 



ft is an inhabitant of the Antilles and Australasia. 



G. ruricola ; Cancer tcrrestrit, Seba ; Cancer ruricola, Linnaeus ; the 

 Land-Crab, Sloane; the Black or Mountain-Crab, Browne; Crabe 

 Violet (?), Labat. Tarsi armed with six rows of spinifonn teeth. 

 Internal edge of the third joint of the jaw-feet without any remark- 

 able fissure. Carapace very large. A few teeth on the internal edge 

 of the carpus. Length rather more than three inches. Colour 

 purplish or reddish-violet, or yellow washed with red. (Milne- 

 Edwards.) 



It is found in the Antilles. 



Land-Crab (Gecarcima ruricola). 



Fouil Gecarciniant. M. Desmarest, in his ' Histoire Naturelle des 

 Crustacea Fossiles," describes and figures a species which he notices as 

 being sufficiently common in collections under the name of Gecar- 

 cinut trit/jinotiu. The same author, in his ' Considerations Gc'nc'rales 

 Kur la C'lassc des CrustaciSs,' alludes to this figure and description ; 

 and observes that he has arranged the fossil, with doubt, under the 

 genus Gecarcinut. M. Milne-Edwards (' Histoire Naturelle des Crus- 

 taceV) expresses bis belief that this fossil is not a Gecarciniaa ; and 

 sayg that it would appear, from the form of the carapace, to approxi- 

 mate more to the genus Pteudoyrapsus. 



GECKO'TID^E, a natural family of Saurian Reptiles, belonging to 

 Gray's sub-order Pacliyylotia, and the tribe Nyctiaura. 



Their head is wide and flattened, with the mouth wide ; the nostrils 

 are distinct and lateral ; the eyes large, hardly surrouuded by short 

 lids, the lower edge of which in the greater number of species docs 

 not project outwards, the pupil sometimes rounded, but most fre- 

 quently dentilated, linear, and lightly fringed ; and the auditory 

 opening bordered with two folds of the skiu. The teeth are small, 

 equal, compressed, sharp at the point, entire, and planted in the 

 internal edge of the jaws : there are none on the palate. The tongue 

 is short, fleshy, capable of but little elongation, and free at its extre- 

 mity, which u either rounded or flattened, or very slightly notched. 



Their neck is apparently little, in consequence of the width of the 

 back part of the head and the squareness of the shoulders. Their 

 body is thick and short, depressed, and low on the legs, with a belly 

 flat below, dragging on the ground, and largest in the middle. There 

 is no crest on the back. The tail varies, but is not long, and often has 

 folds or circular depressions, but never a dorsal crest. 



The feet are short, nearly equal in length, wide apart, and robust ; 

 the toes nearly equally long, most frequently flattened below, widened, 

 and furnished with transverse imbricated plates ; the nails vary, but 

 they are ordinarily hooked, sharp, and retractile. The conformation 

 of the feet enables the Geckos to run with ease on the smoothest 



surfaces in every direction, or to remain stationary on them with tho 

 back downwards, after the manner of a common house-fly. 



The skin is defended by equal granular scales, most frequently 

 interspersed with other tubercular scales, the points blunt or angular. 

 There are femoral pores, or pores in front of the vent, on the same line 

 in the majority of species, and most frequently in the males only. 

 The limbs and sides are sometimes bordered with fringed membranes. 



Skeleton. The skull of the Geckotidte is marked by some peculiar 

 characters. The bones are well defined, nor do the sutures seem to 

 be obliterated by age. In general contour it approaches the skull of 

 the Crocodilidce by its width, its flatness, and its length ; its particular 

 resemblances to the same part in that family are to be found in the 

 disposition of the orbits and in the articulation of the jaws. The 

 excavations for the eyes are very large and apparently incomplete, 

 inasmuch as the orbital frame is not entirely bony in its back part, 

 nor has it, so to apeak, any flooring, so that when deprived of the 

 softer parts the cavity communicates with the mouth. The articula- 

 tion of the jaw is quite backwards, and the os quadratum or interarti- 

 cular bone is wide, short, and hollowed on its posterior surface, for 

 the purpose of receiving the muscle, whose office it is to open the jaws 

 and keep them open. The skull differs from that of the other lizanls 

 generally in the extreme smallness of the jngal and temporal bones, 

 and in having the parietal bones divided longitudinally into two. 



Skull of a species of Gecko, 

 a, cranium ; b, lower jaw ; c, a tooth enlarged. (Cuv., ' Oss. Foss.') 



The vertebra vary in number, and, according to Meckel, their body 

 is hollowed into two conical cavities, very nearly like those of fishes : 

 the spinal column is without any spinous processes or projections. 

 The first three or four cervical vertebra; only are without false ribs or 

 transverse articulated apophyses. These are gradually developed, and 

 go on increasing in length and curvature to the fifth or seventh, but 

 none of them are actually joined to the great anterior portion of the 

 sternum. Those which follow reach and are articulated with that 

 bone. They are succeeded by the free or abdominal ribs, which nearly 

 equal in number the vertebra; which precede the pelvis, at least in the 

 Banded Gecko. 



The sternum in the Common Gecko (Platydac/ylus gutlatus of 

 Cuvier; Gecko verus of Merrem and Gray), consists of a very solid 

 plate, which receives anteriorly and laterally in two angular notches 

 the coracoid bones, which are wide and delicate, and the clavicles, 

 which are narrow, elongated, and flattened, more especially at their 

 sternal extremity. The rhomboid and backward portiou of this 

 sternal plate affords attachment on the two posterior facings to three 

 pairs of ribs. From the posterior or abdominal angle of this bone 

 two small parallel bones or sternal prolongations are given off, along 

 which three other pairs of ribs are affixed by ligaments. After these 

 six pairs of sternal ribs come seven other pairs, which are curved at 

 their free or abdominal extremity into an obtuse angle, so that they 

 are at this end directed forwards without any junction to a mesial 

 line, as in the Chameleons. M. Dumeril says that generally he has 

 only counted 17 ribs, but he observes that there are 24 in the Banded 

 Gecko (Platydactylui vittatw of Cuvier ; Gecko viUatui of authors). 

 Hence M. Dume'ril concludes that the number of ribs varies according 

 to the species. 



The caudal and pelvic vertebra: require notice. The articulation of 

 the former is either weak, or the body of the vertebra itself is apt to 

 break iu the middle, so that a slight effort separates them, and many 

 individuals consequently lose their tails: When these are regenerated, 

 cartilage is generally found in the place of the former bone, and the 

 tail then presents a variety of forms. 



The bones of the limbs do not differ from those of the other Saurians 

 so as to require any particular description, with the exception of those 

 of the feet, and there the difference is striking with relation to the 

 greater portion of the class. In the Geckotldce the bones of the feet 

 are so disposed as to receive the five toes of equal or nearly equal 

 length, and which radiate as it were from a centre so as to form a 

 nearly complete circle ; for the external or great toe cannot separate 

 itself from the others to extend itself backwards. The toes are not 

 always furnished with nails ; but they are often provided with very 

 remarkable ones, which by their mobility and retractility remind tho 

 observer of the organisation of the same parts in the Cats (Fdidoc). 



