40 PROCEEDINGS OF THE ^^ATIONAL MUSEUM. vol.37. 



the inner and lesser trochanters show at once that the femur pertains 

 to a member of the Orthopoda. The situation of the inner trochanter 

 wholly upon the jsroximal half of the shaft at once sejjarates it from 

 the Camptosaurida>. On account of its small size and the fact that 

 no specimen of Di'ijosaurus of these dimensions has been described, 

 it is unhesitatingly referred to the genus Laosauriis, and provision- 

 ally to L. gracilis, the most diminutive species of that genus. Except 

 it differs in a few minor details and is much smaller in size, this bone 

 closely resembles the femur figured " b}- Professor Marsh as Xanosau- 

 rus rex, and which he says " may perhaps belong to the genus Laosmi- 

 inisy That this was the proper disposition of the specimen has been 

 recently pointed out by von Huene and Lull.'' 



The chief interest in the above specimen is its occurrence in the 

 mammal layer, a discovery considered worthy of record. 



Measurcmcnift. 



mm. 



Greatest length of femur T).") 



Greatest width of pi"oxinial end of femur 13. 5 



(Jreatest width of distal eml of femur 12 



Height of lower edge of inner trochanter above distal end of femur 29 



The femur is Cat. No. 5808, U.S.N.M., and was collected by Mr. Ed. 

 Kennedy in " Quarry 9," Como Bluff, Albany County, Wyoming, in 

 1884. 



Several isolated caudal vertebra? I am unable to distinguish from 

 Coelurus fragilis Marsh, and Mr. Barnum Brown writes me that he 

 " remembers finding Coelurus vertebrae in this layer, although none 

 were saved." 



^Vliile two other American species of this genus have been de- 

 scribed, C. graciliii is only known from the Potomac of Marjdand, 

 and C. ag'ilis from the Morrison of Colorado. 



I find among old drawings made for Professor Marsh unpublished 

 figures of the caudal vertebra? which are here reproduced as further 

 elucidating the characters displaj'ed by these bones. (See fig. 3). 

 The type specimen of Coelurus fragilis is from Quarr}^ 13, which has 

 been tentatively correlated with beds from 20 to 25 feet higher in the 

 formation than those of " Quarry 9." 



Figs. 3 and 4, pi. 11, are presented as illustrating forms new to 

 the Morrison fauna, but too fragmentary for satisfactory types, and 

 :>n that account I have deferred naming them. 



Fig. 4, pi. 11, is a portion of the left ramus of a small reptile. 

 The slender jaw is thickly studded witli delicate, round, pointed 

 teeth placed in a single row on the dentary. The anterior teeth are 



o 16th Ann. Rept. U. 8. Geological Survey, for 1894-95, pt. 1, 1896, p. 200, figs. 

 44 to 48. 



^ Neuen Jahrbuch, 1908, p. 142. 



