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FOSSIL REPTILIA OF TFIB 
the comparable structure is by no means peculiar, as Von Meyer would lead one to infer, 
to the skulls of Birdsd 
In no Pterosaurian has any obvious and unmistakeable suture been seen indicative of 
the respective shares taken by maxillary ( 21 ) and premaxillary ( 22 ) in the formation of the 
dentigerous part of the upper jaw : both bones combine to support the array of teeth ; they 
have coalesced, at least at their external or faci-alveolar plates ; as, likewise, have the right 
and left premaxillary portions forming the fore end of the upper jaw. The suture between 
this preinaxillo-maxillary bone and the suborbital portion of the zygomatic arch remains. 
Accordingly, there is a choice of analogies in the interpretation of the observed facts : a 
proportion of the compound bone may be assigned to the premaxillary, according to the 
analogy of the Crocodile and Lizard ; or the whole may be called premaxillary, according 
to the analogy of the Ichthyosaur. 
Goldfuss, guided by the Lacertian analogy, limits the premaxillary to the anterior part 
of the upper jaw, and to the upper part of the external bony nostril {n) ; and he illustrates 
this view by a dotted line representing the assumed suture in his restoration of Ptero- 
dactyliis crassirostris, in pi. ix (op. cit.).^ Von Meyer assumes, as arbitrarily, the Ichthyo- 
saurian analogy, but views it as a specially Avian one, and ascribes to the Pterosauria a 
bird- like premaxillary,® and this determination is indicated by the numerals on the restora- 
tion of the skull of Pterodactylus compressirostris in my Monograph of 1851, quoted below, 
PL XXVII, fig. 5. 
Of the maxillary bone (my 21 ) Von Meyer merely remarks that “ it does not follow the 
type of Birds” (“ folgen nicht dem Typus der Vogel,” ib., p. 15). And yet, if the Pterosau- 
rian premaxillary be interpreted according to that type, forming so large a proportion of the 
upper jaw as to include all the teeth, the edentulous maxillary must have had a correspond- 
ingly Avian proportion and position. Only, whereas in most Birds the small and slender 
maxillary sends up a process helping to define the back part of the nostril and fore part of 
the antorbital vacuity, the corresponding process in Pterosauria would be (as indicated in 
my PI. XVni, 22’'), part of the premaxillary. 
1 incline to believe, however, that it may prove to belong to the maxillary ; that 
the dentigerous part of the upper jaw is due, in Pterosauria, to the combined maxil- 
laries and premaxillaries, but that the latter take a larger share in the formation of 
the alveolar tract than Goldfuss conjectures. One ground of such opinion is this : 
the portion of upper jaw with six pairs of laniary teeth in the huge Pterodactylus 
SedyioicMi, in which the palatal surface could be clearly worked out,^ showed that the 
anterior expansion, with the group of three pairs of teeth, could hardly have been 
‘ “ Zwischen Nasenloch und Aiigenhdhle liegt eine dritte OefFnung, die wiederum an den Vogel- 
schadel erinnert.” — Op. cit., p. 16. 
2 Copied in PI. XXVIT, fig. 4, of my Monograph above cited of 1851. 
3 “ Ein Vdgeln-ahnlichen Zwischenkiefers,” v, p. 15, op. cit. 
Monograph, Suppl. No. 1 (1859), PI. I, figs. 1, a, b. 
