280 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



CAMPTOSAURUS NANUS Marsh. 



Camptosaurus nanus Marsh, Amer. Jouru, Sci. (3), XLVIII, 1894, p. 85, 

 pi. v., fig. 3; 16th Ann. Rep. U. S. Geol. Surv., 1894-95, Pt. 1, 1896, 

 p. 196, pi. LV, fig. 2. 



Camptosaurus nanus Walcott, Science (2), XI, 1900, p. 23. 



Camptosaurus nanus Nopcsa, Foldtani Kozlony, Budapest, XXXI, 1901, 

 p. 210. 



Camptosaurus nanus Hay, Bull. No. 179, U. S. Geol. Surv., 1902, p. 501. 



H olotype.— C?it. No. 2210 U.S.N.M.'^ was collected by Mr. W. H. 

 Reed from the upper Jurassic (Morrison beds), "quarry 13," near 

 Conio, Albany County, Wyoming,'' in 1882. 



The elements preserved are as follows: Portion of atlas, axis, 7 

 cervical, 16 dorsal, 4 sacral, and 34 caudal vertebrtr, numerous cervical 

 and thoracic ribs, right fore limb (scapula, coracoid, humerus, radius, 

 and ulna), 2 femora, 2 tibiae, left fibula, 2 ilia, 2 iscliia, portion of left 

 pubis, 2 metacarpals, 1 carpal, and parts of ossified tendons. 



The original description is as follows: 



The smallest species of the genus C. nanus was not more than 6 feet in 

 length, and perhaps 4 feet in height when standing at rest. One of the striking 

 features of this diminutive species is its long sigmoid scapula, shown in fig. 3, 

 Plate V. This is in strong contrast with the short, straight scapula of C. dispar, 

 seen on the same plate, fig. 2. 



Detailed description. — The cervical vertebra' of the present species, 

 as comjDared with the corresponding parts of the larger forms, show 

 no particular distinguishing characters, although they differ in minor 

 details. 



The entire neck and the first two dorsals remain articulated, and 

 thus the true relationship of these parts is accurately displayed. The 

 neck shows the same graceful upward curve of the cervicals as is 

 found in the related species. The transition of the parapophyses 

 from the anterior lateral border of the centrum of the ninth cervical 

 to the elevated position on the side of the neural arch on the tenth 

 (considered the first dorsal), agrees with the conditions found in G. 

 broioni and in the holotype of C. dispar. 



The odontoid is all that remains of the atlas. The axis, which 

 lacks a poi'tion of the spinous process, is otherAvise very similar to the 

 same bone in O. dispar. The second, or axis intercentrum, is not co- 

 ossified as in the other species. In the narrowness of the ventral keel 

 and the deep lateral depressions on the sides of the centra the re- 

 maining cervicals appear to approach the vertebra? of C hrowni 



"Marsh's original accession number is |l56l|. No. 1881 is the number under 

 which this specimen was catalogued while in the Yale University Museum. 



^Bull. No. 179, U. S. Geol. Surv., p. -Wl. Hay gives the locality as Wyo- 

 ming (?). On the original field labels found with the specimens the locality 

 was given in full, and may now be considered as absolutely determined. 



