70 The Ottawa Naturalist. [October 



vertical rows occupying about seven-eighths of the total length of the 

 bone. 



Pterygoid. Is a thin bone of complicated shape in contact with 

 the quadrate, palatine, maxillary, ectopterygoid, basisphenoid, paras- 

 phenoid and probably the vomer. It consists mainly in its upper part 

 of an anterior and a posterior alar extension directed upward and 

 forward, and upward and backward respectively. Both wings are thin 

 and narrow rapidly upward. From either end of the base a short 

 extending spur is developed. Internally the bone is strengthened by 

 two large flanges, united above, and diverging downward to opposite 

 ends of the base. At the centre of the superior border, between the 

 wings, is an inwardly facing concave surface for attachment to the 

 process of the basisphenoid. Sutural union with the quadrate is 

 effected by the application of the external face of the posterior wing 

 to the inner face of the flange of the quadrate, also the posterior basal 

 spur fits into a narrow concavity at the base of the flange of the 

 quadrate, further strengthening the union of the two elements. The 

 anterior basal spur curves outward and forward on the posterior end 

 of the maxillary, and a short distance higher up the postero-maxillary 

 process passes externally back on the anterior border. Above the 

 maxillary contact the front edge of the anterior wing for its full height 

 is overlapped externally by the posterior border of the palatine. Above 

 the anterior basal spur is a moderately large surface marking the 

 external application of the posterior expansion of the ectopterygoid. 

 The upper end of the anterior wing is apparently applied to the 

 parasphenoid, and probably effects a junction with the hinder end of 

 the vomer. 



Palatine. Is irregularly triangular in lateral outline, is highest 

 in front, and narrows downward and backward to the nearly straight 

 base. It is plate-like, and is suturally united to the maxillary, jugal 

 and pterygoid, and in position extends upward at a high angle inward- 

 ly above the postero-superior border of the maxillary. The anterior 

 border is moderately thick and shallowly emarginated in its upper half 

 to form the posterior border of the posterior nares. Antero-inferiorly 

 is a roughened surface for contact with the jugal within the lower front 

 angle of the orbit. Behind the jugal contact the palatine rests on the 

 postero-superior border of the maxillary back to and slightly on to 

 the posterior maxillary process. Thence forward and upward it out- 

 wardly overlaps the front border of the anterior wing of the pterygoid, 

 rising to as great a height as that element. Infero-posteriorly it 

 develops a thin internal process between which and the main termina- 

 tion of the bone the ascending anterior border of the pterygoid fits. 

 Antero-superiorly it apparently has no connection with the vomer, the 

 pterygoid intervening. 



