184 A PYCNODONT FISH OF THE GENUS MESOt>ON. 



with opercular apparatus approximately 0-075111. Its most striking 

 feature is the humped shape of the back. 



As seen in direct side-view, the snout is acutely pointed and 

 prominent, while the profile of the head is sinuous and steep, 

 rising to the elevated occipital crest (pec.}. Nearly all the 

 external surface of the constituent bones is destroyed, but 

 tubercles on the front edge and on the parietal region indicate 

 that it was originally ornamented with a coarse granulation. 

 Being fractured, the bones exhibit their light and open texture. 

 The large and thin mesethmoid (eth.} as usual, extends upwards 

 to the orbit (orb.} ; and since all the cheek-plates are removed, 

 remains of the delicate pterygopalatine arcade are exposed, 

 apparently connected in the ordinary Pycnodont manner * with 

 the base of the cranium. Traces of the relatively large 

 hyomandibular are also seen behind. Teeth occur along 

 the oral edge of the vomer (v.} t but their arrangement cannot be 

 determined. The greater part of the right splenial (r. spl.} is 

 shown from the oral face, being only obscured behind by a 

 fragment of the corresponding bone of the left side. The 

 arrangement of the splenial dentition is thus clear (Fig. 2). 

 The principal teeth are in a regular close series, all of them 

 broader than long and destitute of any coronal pit or crimping. 

 On the inner side of the series there is only one row of small 

 teeth, which are also closely arranged, nearly round though 

 tending to be longer than broad, and with an occasional trace 

 of an apical pit or crimping. There are three outer rows of 

 closely arranged, nearly round teeth, of which the first and third 

 are about as large as the inner row, while the second is slightly 

 smaller. Few of these teeth exhibit the slight coronal pit and 

 crimping. 



The axial skeleton of the trunk is sufficiently well preserved in 

 parts to demonstrate the absence of vertebral centra. The 

 elongated rather stout neural spines are seen in undisturbed 



* A. S. Woodward, " On the genus Anoineeodus, with Remarks on the Structure 

 of the Pjcnodont Skull," Geol. Mag. [3], Vol. x. (1893), p. 487, pi. xvii. 



