1913] The Ottawa Naturalist. 23 



formation of Converse County, Wyoming, U.S.A., a specimen 

 remarkable for the completeness of the skin impression which 

 has been made the subject of a recent memoir by Professor 

 Henry Fairfield Osborn.** 



The phalangeal formula of the fore foot of this specimen of 

 Trachodon annectens is given by Mr. Brown as being 



Digit II with three phalanges, the third a hoof . 



p-.. , T TT " " " " " " 



Digit 111 



Digit IV " " " no hoof. 



Digit V " " " " " 



It is thus evident that this formula, as interpreted by Mr. 

 Brown, is not applicable to the family Traehodontidae as a 



whole. 



In the Red Deer river Trachodon from the Edmonton beds 

 the fore feet were in the position indicated in plates I and III. 

 In removing the rock particular care has been taken to keep 

 each bone in the exact position in which it was found, so that 

 anv observer of the mounted skeleton, or any reader of this 

 paper, with the aid of the illustrations provided, would be in a 

 position to interpret for himself the phalangeal formula presented. 

 This policy of nondisturbance of the bones has been carried out 

 in the preparation and mounting of the entire skeleton. 



In both hands the metacarpals II, III and IV are grouped 

 /ogether in close contact, whilst the fifth metacarpal lies some- 

 what apart. 



In the right manus the dorsal surface of digit II, and the 

 palmar surface of the other three digits are presented to view. 

 Owing to the pressure to which the specimen has been subjected 

 digits IV and V have been brought to the same level as digit III. 

 Digit II is at a higher level, directly over and pressed down on 



digit III. 



In the left manus the palmar surface of digits II and III, 

 and the dorsal surface of digits IV and V are uppermost. Digits 

 II and III He in the same horizontal plane whilst digits IV and V 

 are at a higher level, digit IV resting on digit III. 



The right ulna and radius are seen from behind, and the 

 left ulna and radius obliquely from without and behind. 



The ulna and radius in each arm, and some of the meta- 

 carpals and phalanges, shew the effect of vertical compression, 

 to a varying extent, in an exaggerated breadth. This distortion 

 is given in the accompanying figures, but is probably most cl earl y 

 expressed in plate III, reproduced from a photograph. 



** Memoirs Am. IVhis. Nat. Hist., new series, vol. I, part II, Integu- 

 ment of the Iguanodont Dinosaur Trachodon, pp. 33-54, plates V-X, 

 with seventeen text figures. New York, 1912. 



