Ill 



THE SKELETON 



The literature dealing with the osseous skeleton of the Salamander 

 is very extensive, so that anything approaching a complete resume 

 would be too lengthy to include here; neither would any particular 

 advantage be attained by so doing. All the chief original contribu- 

 tions to our knowledge of the structure and homologies of the various 

 elements, as well as those accounts definitely needing correction, are, 

 however, referred to in the text. 



As an aid to the study of the skeleton in general, and particularly 

 in differentiating between cartilage and bone, it is advantageous to 

 steep the macerated and semi-cleaned bones in a saturated solution 

 of alizarin in alcohol for a few hours. Subsequent immersion in 70 

 per cent, alcohol will extract the dye from the soft tissues and from 

 the cartilage, and leave the osseous parts stained a bright magenta. 



, THE AXIAL SKELETON 



I. THE VERTEBRAL COLUMN (PLATE III). 



1. General. 



The total number of vertebrae is somewhat variable, the most 

 variable region being the tail, the average being about forty. Funk 

 (1827) gives forty-two as a definite number, but a specimen with as 

 few as thirty-eight has been counted, while List (1883) mentions an 

 example having forty-three, and Hoffmann (1873-8) gives a total 

 of forty-four. Four regions are distinguishable, namely, the cervical 

 with one vertebra, the trunk with thirteen to fifteen, the sacrum with 

 either one or two vertebrae, and the caudal region with some twenty- 

 two to twenty-five. Funk further distinguishes a thoracic region, 

 but the term 'thorax' is a misnomer when applied to an Amphibian. 



2. The Cervical or Atlas vertebra. 



The Cervical or Atlas vertebra (Figs. 10 and 11) differs rather 

 widely from the general pattern. The centrum is almost non-existent, 

 being present only at the posterior end at the articulation with the 

 second vertebra. The neural arch is high and bears a well-formed 

 neural spine (nl.sp.). It slopes off obliquely at the anterior end so as 

 to leave a gap between the occipital region of the skull and the arch 



