II* 



AMPH11SIA. 



AMI'HlllIA. 



156 



intermaxillary bond are produced backwards, and the single row uf 

 small pointed tth which they support is opposed to a similar series 

 upon the pranuuiditiulju- IHIIKW In-low. The palatal teeth form a single 

 row on each of the broad bones which correspond with thoie described 

 !> i 'uvier a* the divided voiner in the higher Batracbiana, and extend 

 backward* upon the pterygolds, which support a few teeth. 



The three preceding genera are perennibranchiato, and though the 

 I'rulrtu, like them, always retains lU external gills, it offer* a further 

 advance to the dentition of the higher Batraohiana, and to that r the 

 A m/Jumma especially. Each intermaxillary bone carries on its alveolar 

 border a row of 8 or 10 minute, fine, sharp-pointed teeth, and each 

 premandibular bone is armed with a greater number of nimilnr but 

 larger teeth, arranged also in tingle series. The palatine bones (two 

 Tomers of Curier) support a row of denticles, similar to the inter- 

 maxillary cresoentio series, and ]>arallel with them ; but Mr. Owen 

 points out that the horns of the palatal dental crescent are continued 

 much farther back, terminating, as in Menobranchiu, on the anterior 

 part of the pterygoid bones. Twenty-four teeth are contained in each 

 half of the crescentic or chevron-shaped aeries," as the arrangement 

 is appropriately designated by the Professor, who adds that the 

 supenor maxillary bones are represented in this form by mere 

 cartilaginous rudiments. 



The Ampkiuma, like the Proteut, presents the Batrachian disposi- 

 tion of the teeth in a single close-set series along the alveolar border 

 of both upper and lower jaws. " The upper series extends along 

 well-developed maxillary and intermaxillary bones, and in the extent 

 of the maxillary and palatal series, especially in Amphiuma tridacli/luiii, 

 the indication of a highly interesting character in regard to the affinities 

 of an extinct race of gigantic Batrachians with biconcave vertebra; is 

 discernible." 



In the Amphiuma the palatal teeth run in a single close-set row 

 along the lateral margins of the vomer, forming an acute angle at its 

 anterior portion, whence the series is extended backwards on either 

 side nearly longitudinally, and parallel with the maxillary teeth. " All 

 the teeth are conical, pointed, slightly curved backwards and inwards ; 

 their points glisten with a yellow metallic lustre," whence Dr. Mitchell's 

 name Chrytodonta, The number of teeth in Ampliiuiaa meant is 

 considerably leas than in Amphiuma tritlactylum. 



" The Menopome exhibits," says Professor Owen, '' the same essen- 

 tially Batrachian condition of the teeth as the Amphiuma ; but in their 

 disposition, and in the disposition and form of the voiner, it makes a 

 near approach to the Caducibranchiate group, and allies itself moat 

 closely with the gigantic Newt of Japan (Sieboldia, Bonap.), and with 

 that equally gigantic extinct species of Newt so noted in palaeontology 

 as the JJumo l>Hurii Tetli of Scheuchzer. In the persistence of the 

 branchial apertures, and the more complex structure of the os hyoides, 

 the Mcnopome however 

 manifests itn generic 

 distinctness from the 

 Sieboldia. The single 

 close-set series of small, 

 equal, conical, and 

 slightly-recurved teeth 

 describes a semicircle 

 on both the upper and 

 lower jaws : the row 

 of similar but smaller 

 teeth on the anterior 

 expanded border of the 

 ilividiil vomer runs 

 par.illi-1 with and at a 

 short distance behind 

 the median part of the 

 maxillary series. The 

 premandibular teeth 

 are received into the 

 narrow interspace be- 

 tween the two rows in 

 the upper jaw when the 

 mouth is cloned. The 

 teeth of the Mcnoponu, 

 as of the Amphiuma, 

 are anchylosed by their 

 base and part of it* 

 outer side to a slightly 

 elevated external al- 

 veolar ridge. 



"SifboUUa. The IV 

 rennibranchiate or Ki.-h- 

 like Amphibia, 'doubt- 

 ful reptiles' as they 

 have been termed, lead by so easy a series of transitions to the 

 Caducibranchiate group, in which all external trace of the branchial 

 apparatus is lost, that the artificial nature of such a division of 

 the order is evident, and some naturalists have even hesitated 

 whether to separate, genetically, the last of the I'vrcnnibronchians 

 from the species SuMaiagiyniitxt. with which the description of the 

 dental system in the higher division of the Batnehiaus is here corn- 



Skeleton of Dnrlytrthra Lalandii. 



The figure* on each tide Dhow the difference of the ntrrmini in the Common Frog, and in the 

 Ltactylrthra ; a represents the sternum of the former ; b that of the latter. 



uieuced. As regards the teeth, the difference between the great 

 aquatic Salamander of the volcanic mountains of Japan and that <.f 

 ili.- Alleghanies is very slight, and merely specific; th. f..nn, .lispocd- 

 tion, and attachment of the teeth are the same in >t '.-././, n as in 

 Mrii'ipome ; tin y ditl. r slightly in the relative size, those 

 Japanese Newt having the advantage in this respect, with a son 

 deeper implnnt.it inn ..| their anchylosed base, and the alveolar parapet 

 of the intermaxillary bones is higher and is slightly i There 



are 14 teeth in each intermaxillary. '- in . ...-h sujx-rior maxillary, 

 and 64 teeth in each Tomer uf the Sulm/ilia i/iiimiim." 



All the Caducibrarul .tils, as the Newts and 



Land Salamanders, have teeth mi the inferior maxillary and vim 

 bones, as well as on the intennaxillaries and superior maxiUaries. 



The Frogs have no teeth on the lower jaw, though in some species 

 (Ceratvpliryi for example) the alveolar edge of the lower jaw-bone is 

 finely notched or dentated. The Bufonidce, as a general rule, are 

 toothless, but in the Jlouibinatora the subgenus f/yladactyltu has 

 teeth upon the vomer, and tidirophryt has teeth on both the inter- 

 maxillary and maxillary bones. 



Hutcular System, pn relating to Locomotion. The 



muscles destined to give activity to the framework, examples of 

 which are given below, are, like those of all the Reptiles, remarkable 

 for their irritability. There are not wanting zoologists who have seen 

 Toads, Salamanders, Tortoises, and Serpents, deprived of their heads 

 and skins, but kept moist, display muscular motion for whole weeks. 

 In the Anourout Amphibia, the Frogs especially, the muscles i>f the 

 abdomen are more developed than in the oil. 



this particular some analogy to the abdominal structure of the 

 Mamtnifers. But it is in the disposition 1.1' tin- niu>. 1. .- i.f the thigh 

 and leg in the Frogs and others of this group, that the greatest singu- 

 larity is manifested. These, whether taken conjointly or singly, ]: 

 the greatest analogy with the muscular arrangement of the same parts 

 ill Man. We find the rounded, elongated, conical thigh, the knee 

 extending itself in the same direction with the thigh-bone, :m.l a 

 well-fashioned calf to the leg, formed by the belly of the gastro. 

 muscles. It is impossible to watch the horizontal motions of a I 

 the water, as it is impelled by these muscles and its webbed 

 without being struck with the complete resemblance in this portion 

 of its frame to human conformation, and the almost perfect identity 

 of the movements of its lower extremities with those of a man making 

 the same efforts in the same situation. 



We have seen that the ribs are absent in the Anourous Amphibia, 

 and the functions of respiration, as well as those of deglutition, being 

 carried on by means of particular muscles, as we shall present K 

 to notice, those bones would have been mere incumbrances. In the 

 Frogs, the muscles are not attached to the skin, which envelops the 



whole muscular arrange- 

 ment in a sort of insu- 

 lated, insensible, move- 

 able bag : in the 

 'i*, on the con- 

 trary, the integuments 

 serve as the point of 

 insertion to almost all 

 the active organs of 

 motion. 



The locomotion of 

 the A nan rout Am- 

 philiia oti land ronsist.1 

 in walking, running, 

 and leaping, in its 

 various modifier 

 the latter being the 

 motion most prevalent. 

 The greater port of 

 them are excellent 

 swimmers; and when 

 they betake themselves 

 to thiaexerei.se, the 1 a ly 

 is extended horizontally, 

 mid tin- animal is pro- 



>y lh. in. elinuiolil 



of the lower extr. mi- 

 ties alone a mechiui ism 

 admirably adapted to 

 this mode of progres- 

 sion, as well as to the 

 other \;n i. ties of move- 

 ment vliiVh tli.- neces- 

 sities of the ami: 

 quire. l'.\ tin- uiil of 

 these well-developed lower limbs, and the prodigious power of their 

 muscular and I., ny level-*, u Frog can raise itself in the air to twenty 

 times its own height, and traverse, at a single bound, a spao 

 than fifty times the length of its own body. 



'Hre Organs. The Anouroui Amphibia, in their adult state, 

 are, like the greater part of the existing Reptiles, carnivorous, and 

 swallow their living prey without mastication. The mouth in many 



