﻿86 PLEISTOCENE MAMMALIA. 



the German and the English specimens, and therefore have not scrupled to use them 

 both in restoring outlines. 



§ 2. Mas (PL XIV, figs. 1, 1', 1").— The only British specimen that we have 

 seen is the central portion, without the transverse processes, of a very fine and large 

 atlas from Sandford Hill Cave, in the Taunton Museum. It is that of a full-grown, though 

 still young animal, and closely agrees in condition aud age with the larger skull in the 

 same collection. It is somewhat larger than a cast from Gailenreuth ; but as it agrees 

 with it in other respects, we have restored the transverse process {pi) by copying that of 

 the German specimen, somewhat larger than nature. 



The centrum of this vertebra being the odontoid process of the axis, 1 that which is 

 often described as the centrum is the " hypapophysis" [hy). It is of moderate thickness, 

 without epiphyses, somewhat thicker centrally than proximally or distally, but showing 

 hardly any trace of the anterior tubercle on the ventral surface, which slight trace, however, 

 afforded origin to the first of the series of five muscles which answer to the " longus 

 colli" in man. The hypapophysis ends proximally in a well-defined notch between the 

 glenoid or proximal zygapophyses {az), and distally in a well-defined tubercle between the 

 axial or distal articulations. This tubercle gives attachment to a strong ligament, the 

 " axo-atloid," which unites the atlas with the axis. The odontoid articulation on the 

 inner surface of the ventral portion of the ring is well defined and slightly raised, having a 

 slightly depressed and roughened space between it and the tubercles for the " transverse 

 ligament" on the inside of each neurapophysis (figs. 1, 1", e). 



The neurapophyses are, as in the recent lion, ample, and of considerable proximo- 

 distal length, and at their symphysis affect the form of a low neural spine that is slightly 

 bifurcated proximally, and affords an attachment for the origin of the " rectus minor 

 posterior capitis." 



The very great projection of the proximal zygapophyses {az) beyond the transverse 

 processes affords a means of distinguishing the atlas belonging to Felis spelaea from that 

 of Ursus spelaus, or U. arctos. In Vrsus maritimus, however, or the Polar bear, the same 

 projection is visible. They are separated by a deep broad notch on the dorsal margin of 

 the ring (fig. 1, o), to which the ligament that bridged over the space between the atlas 

 and the skull was attached, and the dorsal edge of each is interrupted by a small but well- 

 defined notch, which, however, is not constant in the recent lion (fig. 1, b). The distal or 

 axial zygapophyses (pz) form flat broad articulations exactly as in the lion, diverging 

 nearly at right angles from each other, and separated through the greater part of their 

 extent by the entire width of the spinal canal ; but they send prolongations along the 

 ventral edge of the ring, so that they are only separated by the small tubercle mentioned 

 above, which terminates distally the hypapophyses (fig. 1", r). 



i Owen, ' Homol. of Vert Skeleton,' p. 93. 



