254 



SCIENCE. 



[N. S. Vol. XIX. No. 4T0 



On the Finding of Skulls of Trionychidoi 

 in the Bridger Deposits of Wyoming: 

 Dr. 0. P. Hay, American Museum of 

 Natural History. 



More than twenty species of fossil Tri- 

 onyehidaB have been described from the 

 Cretaceous and Tertiary deposits of North 

 America. All these have been based on 

 more or less incomplete shells. No skulls 

 have hitherto been found. During the past 

 summer a party from ■ the American Mu- 

 seum of Natural History was engaged in 

 collecting in the Bridger Eocene of Wy- 

 oming. Among many other turtle remains 

 secured were two skulls of Trionychidse. 

 One of these is very large, having a total 

 length of more than six inches. The lower 

 jaw is missing. The form is strikingly like 

 that of the skull of Platypeltis ferox of the 

 southern states; but the snout is broader, 

 the inter-orbital space is- wider and the 

 choanffi are constricted, as in Aspidonectes 

 sinensis. The species is named Aspidon- 

 ectes tritor. A skull of another species 

 is much smaller and is accompanied by the 

 lower jaw. 



These specimens show that since the 

 Eocene there has been no important change 

 in the structure of the Trionychidfe. Dr. 

 Baur was led to the same conclusion regard- 

 ing the Trionychidffi of the Upj)er Creta- 

 ceous, from the examination of shells and 

 limb bones from the Laramie of Wyoming. 

 Shells from the still older deposits of the 

 Judith River, and Belly River beds sim- 

 ilarly give indications that the members 

 of this group have undergone little change 

 since the early periods of the Upper Cre- 

 taceous. We must, therefore, look to dis- 

 coveries in the fresh-water deposits of the 

 Lower Cretaceous or of the Jurassic for 

 light on this group. 



The Grasping Power of the Manus of Orni- 

 thomimus altus Lanibe: Lawrence M. 

 Lambe, of the Geological Survey of 

 Canada. 



The description of the manus is based 

 on materials found by the writer in the 

 Belly River deposits of Alberta, Canada. 

 The pes of 0. alius shows that the animal 

 was adapted to swift running. The manus 

 can not yet be wholly reconstructed, but 

 the claws were quite different from those 

 of 0. sedens. 0. altus may be regarded 

 as the successor of Ornitholestes hermanni 

 Osborn, and there are many similarities in 

 the manus of the two. The manus of 0. 

 altus is much stouter and less elongate, but 

 it probably had equally great grasping 

 power. The phalanges of what is supposed 

 to be the second finger were described. A 

 channel between the condyles of the distal 

 end of the first phalanx extends through 

 an angle of about 223°. The amount of 

 rotation which the second and distal pha- 

 langes may make is very great. 0. altus 

 probably pursued a rapid prey and grasped 

 it tenaciously with its fore limbs. Evi- 

 dently the claws were long and sharp. 



Oil Some Marine Fossils in the Titanothere 

 Beds: Dr. F. B. Loomis, Amherst Col- 

 lege. 



On Bear Creek, near the Cheyenne River, 

 South Dakota, in the lower part of the 

 Titanothere horizon of the Oligocene, were 

 found about seventy-five baciilites and parts 

 of a Platecarpus, these being Ft. Pierre 

 species. These occurred in concretions and 

 had a limited distribution. Their presence 

 was explained by river action, the fossils 

 having been excavated from the Ft. Pierre 

 and redeposited during the building up of 

 the Titanothere beds. 



Tlic Belationships of the Phytosauria: Dr. 

 J. H. McGregor, of Columbia Univer- 

 sity. 



This group of reptiles, represented by 

 the belodonts of the European and Amer- 

 ican Triassic, were regarded by Huxley as 

 constituting a primitive division of the 

 crocodiles, for which he proposed the sub- 



