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MANUAL OF ZOOLOGY. 



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 ; Ophidobatrac.hia\ This is a small order, 

 including only certain snake-like, vermiform animals (fig. 185) 

 which are found in various tropical countries, burrowing in 

 marshy ground, something like gigantic earth-worms. They form 

 the family Caciliadce (so called by Linnaeus from their supposed 

 blindness), and are characterised by their snake-like form, and 

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



Fig. 185. Ophiomorpha. a Siphonops annulatus, one of the Csecilians, much reduced ; 

 b Head ; c Mouth, showing the tongue, teeth, and internal openings of the nostril.-, ; 

 d Tail and cloaca! aperture. (After Dumeril and Bibron.) 



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- 

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

 tion are filled with the cartilaginous or gelatinous remains of 

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

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

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

 merous delicate, rounded, horny scales, which are dermal in 

 their character, and are wanting in Siphonops annulatus. The 

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

 physis. The teeth are long, sharp, and generally recurved ; 



