AND AYES 01'' NOKTII AMERICA. 



149 



size ; but their centres are distant from the end of the muzzle (measured axially) more than 

 one-third the total length of the cranium. 



The descending portion of the pre-frontal is very wide, and equal to the width of the 

 maxillary outside the lachrymal foramen; the hitter is small. Internally, the columns of 

 the prefrontals converge below to nearly an acute angle, and are directed forwards along 

 the vomer. They restrict the nasal meatus extensively, leaving its diameter less than that 

 of the columns. On the muzzle the pre-frontals have hut a short common suture, admit- 

 ting the frontal far between them. The internal nostrils have a diameter each side the 

 septum equal to that between the pre-irontals. 



EUCLASTES PLATYOPS. Cope. 



Premaxillai'ies narrow, rounded in front; maxillary outline, nearly straight to below anterior rim of orbits, 

 where the breadth of the muzzle is 4 inches, length to end of muzzle only 3. Piano from top of prefrontals to maxillary 

 margin straight, oblique maxillary margin with a gentle sigmoid flexure; Squamosal much expanded below and behind 

 orbits, Frontal region flat, parietal rising behind; nasal meatus subquadrate, slightly narrowed below, its palatal fora- 

 men with a free lateral osseous margin. Alveolar ridge divergent, little projecting above the oblique surface; the 

 latter is most concave behind on each side of the vomer, presents no ridges, and few nutritious foramina. lane of 

 common suture of o. o. max ilia ria in front of vomer, in a. sulcus. Palatines cuneiform with e veiled margins posteri- 

 orly, latter most elevated on each side the small choanal opening, which is bounded in front by the projecting posterior 

 knob of the vomer. The mamillaries are very massive, and underlie more, than two-thirds the area of the orbits; they 

 receive a, very extensive descending portion of the prefrontals, their union extending so far towards the median lino 

 as to leave but a, narrow nasal meatus. This oilers a, powerful resistant face to the motion of the mandibles. The 

 posterior orbital margin is .75 inch in thickness, and is at right angles to its alveolar margin. Pterygoids almost 

 entirely broken away. The following measurements will furnish the best data for a comprehension of the form in 

 detail. 



Total length cranium, 

 Breadth behind orbits, 



" between poster, margins orbits, 

 Least interorbital width, 

 Width of nasal meatus, 

 Depth premaxillaries, 



" maxillary at middle orbit, 



" squamosal at zygomatic arch, 

 Length naso-prefrontals, 



common suture, 



" common suture frontals, 



" from anterior margin orbit to nasal meatus, 

 " premaxillary margin to end vomer, 

 Width posterior nares together, 



" palatine bone opposite end of vomer, 

 " vomer near anterior extremity, 



Greatest diameter of orbit, 



Least " " 



AMERI. PHILOSO. SOC VOb. XIV. 38 



In. 



Lin. 



11 





8 



(5. 



5 



2.5 



2 



2.5 



1 



2.5 



1 



1. 



1 



3.8 



2 



O 



2 



3. 





0.3 



2 



4. 





11. 



3 



(). 



1 



1.5 





.!) 





.7 



2 



.0 



