700 



SCIENCE. 



[N. S. Vol. XVIII. Xo. 465. 



mentioned the small fauna of tlie lower 

 Pleistocene which has been found in caves of 

 California and in fissure deposits in northern 

 Arkansas, which promise to give us a nearly 

 complete knowledge of the Lower Pleistocene 

 microfauna of North America. 



TRIASSIC REPTILU.. 



The comparatively little known Eeptilia of 

 the Trias are now receiving more attention. 

 Von Huene* has published in Palceonto- 

 graphica quite an elaborate review of all the 

 Triassic reptiles, including also the large 

 amphibian Stegocephala of the Lower Trias 

 as well as the South African forms. 



Dicynodonts. — Dr. K. Broom| is contrib- 

 uting a series of very important papers on 

 the South African Dicynodonts. One of the 

 first of these, on the structure and afiinities of 

 Udenodon, appeared ia 1901. In this genus 

 as well as in Dicynodon he finds marked sexual 

 characters or differences between the supposed 

 males and females in the structure of the 

 canine teeth and the massiveness of the lower 

 jaw. 



Theriodonts. — Among the Theriodonts the 

 same author^ finds two widely different types 

 of palatal structure and he selects Scylaco- 

 saurus as the type of a new order, Thero- 

 cephalia, to include the most primitive of 

 the Theriodonts. It is possible that the higher 

 typical Theriodonts, such as Gcdesaurus and 

 Cynognathus, are descended from the Thero- 

 cephalians ; but the gap , between the two is 

 very great. 



From Aliwal North he records § a very sur- 

 prising discovery of the lower jaw of a small 

 mammal which is named Karoomys Browni, 

 probably the oldest mammalian jaw which has 



*Uebersiolit fiber die Eeptilien der Trias,' 

 Palaeontographica, 1902, pp. 1-84, tab. I.-IX. 



f ' Remarks on Certain Diflterences in the Skulls 

 of Dicynodonts, Apparently due to Sex,' Proc. 

 Zool. Soc. Lond., June 3, 1902. 



J ' On the Structure of the Palate in the Primi- 

 tive Theriodonts,' Geol. Mag., Decade IV., Vol. 

 X., No. 470, August 1903. 



§ ' On the Lower Jaw of a Small Mammal from 

 the Karoo Beds of Aliwal North, South Africa,' 

 Geol. Mag., December IV., Vol. X., No. 470, Au- 

 gust, 1903. 



yet been discovered. The jaw, although of 

 greater geological age, remotely suggests that 

 of Microconodon from our Upper Triassic. 

 The angle is well developed and but very 

 slightly inflected. The author considers that 

 its nearest allies are probably to be found 

 among the Jurassic forms, such as Diplocy- 

 iiodon Marsh. 



Vomer and Prevomer. — Another paper by 

 the same author on the mammalian and rep- 

 tilian vomerine bones* advances the theory 

 that the true vomer in mammals is repre- 

 sented by the parasphenoid of Huxley, a very 

 large element in the Ichthyopsida and reduced 

 or wanting in the Sauropsida. It is main- 

 tained further that the so-called vomers of 

 reptiles are entirely distinct elements, to 

 which the name ' prevomer ' should be given. 

 These are represented by the ' dumb-bell bone ' 

 of Monotremes, and by vestigial elements in 

 Cheiroptera. The true mammalian vomer is 

 a single median element developed between 

 the united trabeculse, while the Sauropsidan 

 prevomer is a paired element formed in con- 

 nection with the nasal capsules. Both ele- 

 ments exist in the Amphibia, and in general 

 the prevomers are enlarged and the vomers 

 reduced in Eeptilia, while in Mammalia the 

 prevomers are reduced and the vomers en- 

 larged. 



The same authorf transfers the genus Pro- 

 colophon, which has always been considered 

 related to the solid-skulled Cotylosauria, to a 

 group related to Sphenodon with two distinct 

 temporal arches. 



CRKTACEOUS REPTILES. 



Mosasaurs. — Baron Pranz Nopcsa, Jr.,:}; 

 traces the great marine lizards, or Mosasaurs, 

 back to the Aigialosaurs, which differ from 

 Mosasaurs only in not being so thoroughly 

 adapted to pelagic life. These reptiles, which 

 were found in the Lower Cretaceous of Dal- 



*'0n the Mammalian and Reptilian Vomerine 

 Bones,' Proc. Linnean Soc. of New So. Wales, 

 1902, Pt. 2, October 29. 



t ' On the Remains of ProcolopJion in the Albany 

 Museum,' Records of the Albany Museum, Vol. I., 

 No. 1, p. 8. 



X ' On the Origin of the Mosasaurs,' Geol. Mag., 

 Decade IV., Vol. X., No. 465, p. 119, March, 1903. 



