48 



ANATOMY OF VERTEBRATES. 



43 



w 



nw^- 



Skeleton of the Menoponie 

 M. AUeghannienae, 



or Protonopsis 



half of the transverse process : they are wanting 

 in the twenty-one following vertebras, and re- 

 appear, well developed, in the thirty-first, where 

 they form with cartilaginous haemapophyses, a 

 pelvic arch. In the Menoponie, fig. 43, the 

 second to the nineteenth vertebras support short 

 straight plenrapophyses, articulated to the ends 

 of transverse processes formed by par- and di- 

 apophyses, which intercept by their terminal 

 confluence an arterial canal. These processes, 

 t, are enlarged in the twentieth vertebra, s, and a 

 second rib-like piece, 62, the homotype of the 

 second part of the scapula in fishes, is articulated 

 to the short and thick rudimental rib, ]>l ; the 

 inferior or haemal arch 63, 64, being cartilaginous. 

 The segment thus completed by the haemal arch, 

 represents a so-called ' sacral ' vertebra : the 

 second division of its rib answers to the ' ilium,' 

 62, and the haemal cartilage to the ' ischium,' or 

 ' pubis.' Transverse processes t, progressively 

 decreasing in length are developed from the six 

 succeeding vertebrae. Bony pleurapophyses pi, 

 are attached to the first of these, and cartila- 

 ginous rudiments of the same element to the 

 three following. Haemal arches are anchylosed 

 to the under part of the centrum of the second 

 to the twelfth caudal vertebra inclusive, and 

 these become more compressed to the end of the 

 tail, for the support of a vertical fin. The neural 

 arches are broad, depressed, anchylosed to the 

 centrum : they are complete to the fourteenth 

 caudal vertebra. The body of the atlas pre- 

 sents an odontoid process between the two arti- 

 cular surfaces for the occipital condyles ; it is 

 deeply cupped behind, as are the succeeding 

 vertebra? at both ends. This vertebra has neither 

 di- nor pleur-apophyses. 



The skeleton of the Newt ( Triton) resembles 

 that of the Menoponie in its general characters ; the 

 neural and haemal spines are more produced in the 

 long tail, supporting there the chief swimming 

 organ of this aquatic batrachian. In one kind 

 the ribs are more developed, occasioning the sub- 



