22 The Ottawa Naturalist. [May 



averaging about \ of an inch in diameter, are here seen to form 

 oval shaped clusters, from 2 to 3 inches in maximum diameter, 

 surrounded by small tubercles, about Va of an inch in average 

 diameter, occupying the intervening spaces, which arc about 

 f of an inch across. 



Of particular interest is the lattice-like arrangement of the 

 ossified tendons in three tiers, or layers, on each side oftheneural 

 spines of the back. These rod shaped tendons have been known 

 to occur in Trachodon, but in no specimen, so far as the writer 

 is aware, has their exact disposition been revealed and described. 

 In the Red Deer river specimen of last summer's collection some 

 of the tendons are seen to fork, or bifurcate, and their arrangement 

 in a triple series is shewn in a very clear and perfect manner. 

 A somewhat similar disposition of ossified tendons, in a double 

 series, in the back and tail has been suggested in published 

 descriptions of Iguanodon and Camptosaurus. 



The Red Deer river specimen is in an excellent state of 

 preservation as a whole, and is one of the most complete of the 

 skeletons of Trachodon mounted in the museums of this con- 

 tinent. As it is unusual to find the front feet with most of the 

 bones represented, and but little disturbed, a short description 

 of them is here given. It is proposed to publish, at a later date, 

 particulars regarding- the shape and position in this skeleton of 

 the ossified tendons, and of such other structural characters of 

 interest as further study of the osteology of the individual mav 

 bring to light. 



Of the four digits in the manus all the phalanges are re- 

 presented with the exception of the terminal one of digit II. 

 As digits III, IV and V ended distally in a hoof (or nail) carrying 

 bone it is probable that digit II, the inner finger, bore a terminal 

 hoof-phalanx also. 



The phalangeal formula presented by this specimen is as 

 follows : 



Digit II. .Three phalanges, the terminal one presumably a 

 hoof-bone. 



Digit III. .Three phalanges, the terminal one a hoof-bone. 



Digit IV. .Two 



Digit V.. " 



This formula differs materially from the one given by Mr. 

 Barnum Brown in a paper entitled "The Osteology of the Manus 

 in the Family Trachodontidae*" and descriptive of the fore foot 

 of a specimen of Trachodon annectens (Marsh) in the American 

 Museum of Natural History, Cat. No. 5060, from the Lance 



* Bull. Am. Mus. Nat. Hist., vol. xxxi. art. x, pp. 105-107, fig. 1 . 

 Nru York, U.S.A., Mav 28th, 1012 



