EXTINCT AMPHIBIA. 379 



small, and situated on the lower surface of the head, and there are two rows of teeth on the mandible. 

 The two nostrils are well in front on the muzzle. One of them is found in the warmer purls of 

 North America, growing to the length of twenty-three inches,* and having the thickness of a good- 

 sized worm. It is agile under ground, moving in its own or other burrows ; but little is known 

 about its habits. It has some short conical teeth in the jaws and palatine bones, and has a little 

 pit on the head on each side beneath the nostril, which is rather projecting. Certainly, during 

 adult age, there are lungs, one, the right, being larger than the other, and there are no gill-clefts. 

 But J. Miiller states that when young there are internal branchiae opening outwards through a 

 cleft, in one kind, whilst it is certain that in other kinds the young are born breathing through 

 lungs. But Gervais and Peters state that large vesicles, branchial in character, are found on the 

 neck of the recently hatched individuals. The vertebrae are numerous and the centra are arnphi- 

 coelous, and they have minute ribs. As in the other Amphibians, there are two occipital condyles 

 to the skull and the hyoid bone, and the persistence of its arches would indicate that there is 

 much to be learned regarding the early condition of these animals. 



Mexico and the Brazils have another genus with a short muzzle and a broad and annulated 

 body, and the pit is situated between the eye and the nostrils, t In Ceylon there is a flat-headed 

 species with a pit in front of each eye,} and in Cayenne one exists without this little place 

 at all. 



There are some peculiarities in the skulls of these burrowing worm-like Amphibia which 

 Huxley has pointed out were foreshadowed in the great extinct Labyrinthodontia of the early age 

 of Reptiles. The skull has a complete bony roof, and there is a quadra to-jugal bone besides the 

 membrane bone, or temporo-mastoid. There is also a bone which seems to be the side nose-cartilage 

 ossified, and another encircles the orbit, having no resemblance to any bone in the other living 

 Amphibia, Moreover, the palate bones surround the back and outer edges of the inner nostrils. 



CLASSIFICATION OF THE FAMILIES OF THE CLASS AMPHIBIA. 







ORDER AXOUHA (BATRACHIA PROPER). 



( Family Pipidae. 



SUB- ORDER AOLOSSA ...,... Dactylethridae. 



( ,, Myobatrachidse. 

 SUB-ORDER PHAJ-EROGLOSSA, I Family Kanidae. 



Pelobatidae. 



Bufonidaj. 



GROUP OXYDACTYLA ..... Rhinophrynidw. 



Rhinodermatidte . 



GROUP DlSCODACTYLA 



En<*y stomatida) . 

 Family Hylidffi. 



Phvllomedusidae. 



Dendrobatida?, 

 ORDER UROPELA, 



/ Family Molgidai. 

 \ Salamandridaj. 



SUB-ORDER SALAMANDRIXA ...... j piethodontidse. 



( Amblystomidae. 



SUB-ORDER ICHTHYOIDEA. r Family S,irenida3. 



GROUP PEBENNIBRANCHIATA ..... ) Proteida?. 



( ,, Menobranchidaa, 

 ( Family Amphiumidae. 

 SUB- GROUP DEROTREMATA ..... j Menopomidte. 



ORDER APODA ........ . Family Cascilidae. 



( GROUP GAXOCEPHALA. 



I* 



MlCROSAURIA, 



( 



THE EXTINCT AMPHIBIA. 



The most ancient Amphibia appear to have first lived during the Carboniferous age, and 



all were tailed, had pleurodont teeth, simple in their construction, and apparently there were no 



bony branchial arches present. The vertebral centra were ossified. Some were Lizard-like and 



others were more Serpentiform, and one genus probably had no limbs. They are the Microsauria 



* CcecUia lumbricordes. T Epicrium hypocyanea. }. Siphonops annulata, Rhinatrema livittata. 



