No. 2389. FAUNA OF THE MARYLAND ARUNDEL— GILMORE. 585 



New Jersey is found the nearest approach to the straight ventral 

 border of the specimen under consideration. 



Although fully recognizing the inadequate nature of the type 

 material the resemblances pointed out above appear highly significant, 

 and taken in conjunction with their similar geographical distribution 

 leads me to believe its assignment to Dryptosawus to be the logical 

 disposition of this species at this time. 



COELURUS? GRACILIS Marsh. 



Plate 110, fig. 5. 



Coelurus gracilis Marsh was also established on a very poor specimen 

 consisting of an ungual phalanx, the tip of which is missing, as shown 

 in plate 110, figure 5. 



The original description is as follows: 



The smallest Dinosaur found in these deposits is a very diminutive carnivore, 

 apparently belonging to the genus Coelurus. It was not more than one-half of the 

 size of the western species and its proportions were extremely slender. The bones 

 are very light and hollow, the metapodials being much elongated and their walls 

 extremely thin. An ungual phalanx of the manus measures about 25 mm. in length 

 and 14 mm. in vertical diameter at the base. This animal could not have been 

 more than 5 or 6 feet in length. 



One would infer from the above description that Marsh had other 

 bones besides the ungual, but I find none in the collection which 

 could by any stretch of the imagination be so referred. 



Three teeth in the Goucher College collection were referred by 

 Lull to this form, two of them having come from the same locality as 

 the type. These, of course, have been arbitrarily associated. The 

 comparison of these teeth with the tooth of Coelurus fragilis, figured 

 by Marsh 1! from the Morrison and which Lull has shown differ con- 

 siderably in the almost total reduction of the crenulation of the 

 anterior convex border, and their larger size, offers but little assist- 

 ance in getting at the true affinities of these teeth. Furthermore, as 

 I have shown, 14 the tooth of C. fragilis does not belong to the type 

 materials, it having been received at the Yale Museum some time in 

 advance of the type, so there is no evidence of their association. 



That the (type) ungual pertains to the fore foot of a small carniv- 

 orous dinosaur there can be no question, but that it is referable to 

 the genus Coelurus remains to be demonstrated. In the present state 

 of our knowledge of the carnivorous dinosauria I doubt the possi- 

 bility of determining the genus to which it belongs, at least with any 

 certainty of the correctness of the identification. 



A careful comparison of the type specimen has been made with all 

 available carnivore unguals in the collections of the United States 



" 10th Ann. Rep. U. S. Geol. Surv., pt. 1, 1S96, pi. 7, fig. 1. 

 11 Bull. 110, U. S. National Museum, 1920, p. 128. 



