800 H. G. SEELEY ON NEW SPECIES OE 



especially as it throws light on the palatal characters of the genus, 

 the specimen may be deserving of description, although it is less 

 perfectly preserved than the other. It was almost hidden in an 

 ironstone nodule, from which I have, by the permission of Dr. 

 Grierson, extracted it. 



Like all the other crania of Procolophon, this skull is flattened 

 above and of triangular outline ; but in the median line it is rounded 

 from the nasal region above down to the anterior termination of the 

 palate, and in front of the orbits appears to taper rapidly, though 

 this may result partly from accidental lateral compression. The 

 bone-tissue is entirely removed from the front part of the skull ; 

 and on the left side the circular narine, T 2 ^ inch in diameter, is seen 

 to have looked downward and outward; the nares extend to the 

 extremity of the skull, much as in Uromastix, and, though separated 

 by the premaxillaries, do not appear to have been divided by a ver- 

 tical bony septum. There is a slight compression behind the nares, 

 and then succeeds the region of the lateral preorbital inflation, 

 bounded above, on the cast, by two ridges which converge forward. 

 These ridges terminate backward in a line with the narrowest part of 

 the frontal bone, which is between the orbits, and they are prolonged 

 forward to the anterior termination of the skull. From the front 

 of the ovate foramen parietale to the end of the snout measures 

 1-^y inch. The least width of the frontal bone is -fe inch. The 

 posterior borders of the orbits are in a line with the hinder limit 

 of the parietal foramen. The length of the orbit is ^ inch ; from 

 above downward it measures -f^ inch. The upper surface of the 

 skull is an inch wide behind the orbits ; but the malar arch bulges 

 outward and the skull reaches its greatest width at the articular 

 portion of the quadrate bone. The malar bone originates at the 

 anterior border of the orbit, and is a flat thin bone less than y 2 ^ inch 

 deep. At the middle of the orbit it bends, and widens in a trian- 

 gular form, extending above and below so as to reach along the 

 entire height, T 8 <j inch, of the quadrate bone. The length of the 

 malar is rather more than its height ; it is concave from above 

 downward in its expanded hinder part, where it joins the quadrate 

 bone, which in side view was vertical, though directed somewhat 

 outward. The malar bone shows no certain sign of division, or evi- 

 dence that it included a quadrato-jugal element. Many lizards with 

 a complete orbit, such as Calotes, have the malar bone expanded and 

 reaching far back, and joined by ligament to a thin wing of the 

 quadrate bone, which curves outward and forward towards it, ap- 

 proximating towards the condition seen in these fossils. Resting 

 upon the hinder part of the malar bone, and resting upon it supe- 

 riorly so as to form the oblique hinder and inferior border of the 

 orbit, is a thin bone y L- inch deep and from y%- to T ^ inch long, 

 which occupies the usual position of the postfrontal bone in lizards, 

 and appears to underlap the outer wing of the frontal bone at the 

 hinder and upper limit of the orbit, on the lizard plan, but is in the 

 position of the quadrato-jugal in Hatteria. The broad flattened 

 superior surface of the skull behind the orbits (1 T 2 ^ inch wide), with- 



