ORDERS OF AMPHIBIA. 



409 



being now placed at the head of the Fishes, under the name 

 of Dipnoi. Whilst there is a general agreement as to the 

 number and characters of the Amphibian orders, the names 

 employed to designate them are very various, and it really 

 matters little which are adopted. 



Order I. Ophiomorpha, Owen ( = Gymnophiona, Huxley ; 

 Apoda of older writers ; Ophidobairachia). — This is a small order, 

 including only certain snake-like, vermiform animals, which are 

 found in various tropical countries, burrowing in marshy ground, 

 something like gigantic earthworms. They form the family 

 CiEciliadce (so called by Linnaeus from their supposed blind- 

 ness), and are characterised by their snake-Hke form, and by 

 having the anus placed almost at the extremity of the body. 

 The skin is quite soft, but differs from that of the typical 

 Amphibians in mostly having small horny scales embedded in 

 it. Another fish-like character is that the vertebrae are amphi- 

 coelous or biconcave, and the cavities formed by their apposi- 

 tion are filled with the cartilaginous or gelatinous remains of 

 the notochord. The body is cyUndrical and worm-like, and is 

 completely destitute of limbs. The skin is glandular, naked, 

 and viscous, thrown into numerous folds, and containing nu- 



Kig. 155. — Ophiomorpha. a Sipkotwps ann-ulaius, one of the CceciUans, much reduced 

 i Head ; c Mouth, shoeing the tongue, teeth, and internal openings of the nostrils ; d 

 Tail and cloacal aperture. (After Dumeril and Bibron.) 



merous delicate, rounded, homy scales, which are dfermal in 

 their character, and are wanting in Siphonops annulatus. The 

 mandibular rami are short, and are united in front by a sym- 

 phy.sis. The teeth are long, sharp, and generally recurved j 



