122 OPHIOMORPHA. 



lobes of liver many, in numerous transverse lamellae; 

 bones of skull soldered together; orbits of eyes covered 

 by maxillaries, and resemble a small hole ; maxillary and 

 palatine teeth in two concentric lines ; hyoid bone com- 

 posed of three pair of arches ; ossiculum auditum or audi- 

 tory bone a small plate on the fenestra ovalis ; os quad- 

 ratum soldered immovably to the cranium; rami of low- 

 er jaw united by symphysis at the chin ; occipital con- 

 dyles two ; vertebrae amphicoelous. 



From the above characters it will be seen that the 

 Caeilians are like the Ophidians in, (i) the form of the 

 body; (2) the absence of limbs; (3) the presence of der- 

 mal scales; (^4) the relative size of the lungs; and (5) the 

 teeth, which are long, tapering, and directed backwards. 

 They were in fact classed with the serpents in the writ- 

 ings of Goldfuss, Voight, Cuvier, and the older naturalists, 

 and it was only when Muller discovered the pores at the 

 side of the neck of a young E. ghitinosa, with branchial 

 fringes within upon the corners of the hyoid, that they 

 were assigned their true position. The characters serv- 

 ing to distinguish them from the Ophidia are, (1) the 

 presence of two occipital condyles; (2) the amphicoelous 

 vertebrae and their union with each other; (3) the dove- 

 tailing of the tympanic bone into the cranium, and solidi- 

 fication of the whole ; (4) the symphysis of the lower 

 maxillary and size of the mouth resulting from the man- 

 ner of its articulation; (5) the cloacal aperture round in- 

 stead of transverse ; (6) the presence of internal branchiae 

 in the young. 



They also somewhat resemble sea-eels among fishes 

 in, (1) the amphicoelous vertebrae and cavities filled w T ith 



