ON THE FORE LIMB OF ALLOSAURUS FRAGILIS. 



By Charles W. Gilmore, 



Assistant Curator of Fossil Reptiles, United States National Museum. 



In unpacking, recently, that part of the Marsh collection in the 

 United States National Museum from near Canon City, Colorado, a 

 partial skeleton of a carnivorous dinosaur was found. This is of 

 peculiar interest since it has been determined to belong to the same 

 mdividual as the pelvis and hind limbs described and figured ^ by 

 Prof. O. C. Marsh, years ago, as AUosaurus fragilis. Both fore 

 hmbs and feet are present, and as they differ materially from the 

 fore limb figured by Marsh in the paper cited above, and especially 

 since an associated fore limb of this genus has not previously been 

 known, it was considered important that a description (of the limb 

 and foot) should be published in advance of the remainder of the 

 skeleton, which is now undergoing preparation, a work that wiU take 

 some time to complete. 



The fore limb figured by Marsh in the Dinosaurs of North America,^ 

 plate 1 1 , figure 1 , as being that of AUosaurus fragilis Marsh, is a 

 composite drawing, and, as I will show, is not representative of the 

 genus AUosaurus, but is largely that of Ceratosaurus. 



In going over a lot of tracings and drawings of Theropodous 

 dinosaur bones made for Professor Marsh, a slip of paper in Marsh's 

 handwriting was found, on which he had written instructions to 

 the draftsman for the composition of the AUosaurus fore limb (fig. 1), 

 which reads as follows: 



Fore limb AUosaurus. 



1. Enlarge scapula (1933 as 83.5 is to 100), 



2. Make coracoid to correspond (see Phillips, p. 208). 



3. Draw humerus (1894 nat. size). 



4. Make radius 9^ inches long. 



5. Make ulna 9^ inches long + olecranon. 



6. Enlarge foot as 83.5 is to 100. 



The number 1933 is the catalogue number of the Peabody Museum 

 origmally given to the type-specimen of Ceratosaurus nasicornis 

 Marsh before its transfer to the United States National Museum. 



> Amer. Journ. Sci., vol. 27, 1884, p. 336, pi. 11. 



2 Sixteenth Ann. Rep. U. S. Geol. Surv., 1896, pt. 1. 



Proceedings U. S. National Museum, Vol. 49— No. 2120. 



501 



