356 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxv. 



and one and three- fourths times the length of the fore arm; while 

 in Allosaurus fragilis the hand is about six-tenths as long as the 

 numerous and about equal to the fore arm. The deltoid crest of the 

 New York specimen is broader and more abruptly formed than in 

 Allosaurus fragilis and the bones of the fore arm are much stouter. 

 When the figures of the New York specimen are compared with those 

 of the shoulder girdle and limb published by TVilliston, as mentioned, 

 one finds the resemblances between the common parts to be very close 

 indeed. It seems probable that the American Museum specimen 

 belongs to Creosaurus rather than to Allosaurus. 



4. THE GENERA DEINODON LEIDY, DRYPTOSAURUS MARSH, AND 

 ALBERTOSAURUS OSBORN. 



Mr. Lambe has published a an instructive description of two skulls 

 of a species of carnivorous dinosaur under the name of Dryptosaurus 

 incrassatus. The name Leelaps incrassatus (=D. incrassatus) was 

 first applied by Cope b to two teeth found in the Judith River beds, 

 Montana; afterwards c to a dentary bone from the same region and 

 level and retaining some of the teeth. Later d Cope described under 

 the same name the two skulls which Lambe has made the subject of 

 his communication. These skulls were derived from the beds of the 

 Edmonton series in Alberta, deposits that are probably equivalent 

 to the Ceratops beds of Wyoming. 



Lambe concluded, and without doubt with justice, that the Edmon- 

 ton skulls did not belong to the same species as the teeth and the 

 dentary bone that had originally borne the name Lmlaps incrassatus. 

 He then proceeded to do two things that are open to criticism. He 

 identified the Judith River specimens alluded to as being probably 

 Deinodon horridus Leidy, and then proposed that the Edmonton 

 specimens should hereafter be regarded as the types of Dryptosaurus 

 incrassatus. 



That the Judith River specimens described by Cope do not belong 

 to D. horridus seems evident from the fact that none of the various 

 teeth originally described by Leidy under this name had the trans- 

 verse diameter greater than that parallel with the jaw. As regards 

 the transfer of a specific name from one type to another, it is needless 

 to remark that this is not permitted by the rules of nomenclature. 

 Mr. Lambe should have described those skulls under a new specific 

 name. This was later done by Osborn, 6 who bestowed on them the 

 name Alhertosaurus scwcoph ag us. 



a Contrib. Canad. Palaeont, III, 1904, Pt. 3, pp. 5-27, pis. i-viii. 



6 Proc. Acad. Nat. Sci. Phila., 1870, p. IMS. 



c Idem, 1876, p. 340. 



d Proe. Amer. PMlos. Sue. xxx. L8&2, p. 240. 



e Bull. Amer. Mus. Nat. Hist., XXI, 1905, p. 265. 



