56 



\K\V REPTILES AM) 8TEGOCEPHALIANS FROM 



pterygoid and the palatines i> not found in any other form of the Paraauehia. In 

 Promyttrioiuchtu there is a strong external process of the pterygoids which is underlain 

 by the posterior end of the transverse; the palatine vacuity is represented by a small 

 foramen between the palatine and the transverse, which appears on the lower surface 

 near the posterior end of the transverse. 



The primitive characters of Promyatriosuekw appear in the elevated parieto-squamo- 

 sal arch, the relatively anterior position of the narial opening, 1 and the elongation of the 

 parasphenoid process. The other characters cited are those of the more specialized 

 Parasuckia, and it is evident that the form here described must be placed in the Mystrio- 

 suchid group of the Phytosauridae. The primitive characters are conservative features 

 which are found in at least one other member of the same group and family. 



Comparison with Ammstorhinus. 



Angistorhimis- is in many ways the nearest known form to Promystriosuchus. 

 A consideration of the comparative characters will make more evident the similarities 



V io. 22. — Anffistorhinus, lateral view of skull, after Mehl. 



A. Lateral view of skull. 



B. Upper view of skull. 

 ('. Lower view of skull. 



D. Posterior view of skull, somewhat larger. 

 ix., septomaxillary. other lettering as usual. 



and differences between J'romyslrioHUchus and the other Mystriosuchids. The relative 

 proportions in length of the prenarial and postnarial portions of the skull of .1 ngistorhinue 

 are as 10 : ti.4, or approximately 5 : 3; the antorbital vacuity is elongate and extends as 

 far forward as the anterior edge of the narial opening; the opening is surrounded by a 



1 Queue, in the QeoL u. Paleont. Abhdlg., N. I'., Bd. x, lift, l, a .'>:i, has suggested that the position of the 

 nanal opening ami tin- elongation of the rostrum .-in' two distinct things .- < i > • I that tin 1 retreat of the narei is oonnecti 'l 

 with tie- shortening of the posterior pari of the skull. The relation between the antorbital vacuity and the nans is 

 regarded by him as a phylogenetie character; as the nares retreated the antorbital opening would appear more and 

 nan anteriorly in the skull. 



: Mehl, II <;.. .Journal of Geology, vol. 21, No. '-', p. 186, 1913; /'•<.'.. vol. 23, No. 2, p. 129, mi:,. 



