16 PROCEEDINGS OF THE jSTATIONAL MUSEUM. vol.64, 



statement fully born out by examinatian of a beautifully made cast 

 of the type specimen, secured through the courtesy of Dr. W. D. 

 Matthew of the American Museum of Natural History. Though 

 somewhat similar in size to the modern white-necked ravan, Corvus 

 cryptoleucus — a species now found in semi-desert regions from west- 

 ern Texas and southeastern California, south to Guanajuato and 

 Michoacan, that in the last century ranged north into western 

 Kansas and Nebraska — shufeldti has the strong, robust form that 

 characterizes Corvus corax^ and is allied to it rather than to cryp- 

 toleucus. 



The tibio-tarsus secured near Benson is also of the Corvus corax 

 type, though it represents a bird only about as large as a common 

 crow, Corvus hrachyrhynchos. Careful comparison shows that this 

 specimen comes from a bird slightly smaller than the type of 

 shufeldti. The difference in size between the two is, however, within 

 the possible limit of sexual variation, as shown by a study of a 

 series of Corvus corax and C. hrachyrhynchos. In other words the 

 type of shufeldti might represent a male and the Pliocene bird a 

 female of the same species, a possibility not in conflict with the 

 geological evidence in the case, since there would be nothing to 

 prevent a species (represented by the Benson specimen) that existed 

 in the upper Pliocene from extending its range during the milder 

 climate of the first interglacial period (when it is supposed that the 

 Fossil and Silver Lake deposits were formed) to the region in south- 

 central Oregon where the type of shufeldti was secured. On the 

 other hand the Benson specimen may represent a distinct species, 

 a matter that is left in abeyance until further material may be 

 available. 



Following is a detailed description of the tibio-tarsus secured by 

 Doctor Gidley : Inner and outer malleoli nearly similar in form and 

 size but the inner one slightly wider in transverse diameter on 

 external face; intercondylar sulcus broad, divided by a low but w^ell 

 marked ridge that begins on the posterior face at the level of the 

 upper margin of the condyles and passes down to end abruptly at 

 the lowest point of the sulcus, where it is abruptly delimited by 

 the margin of the intercondylar fossa, so that it does not extend 

 around on anterior face of sulcus; intercondylar fossa, for the recep- 

 tion of the intercondylar process of the tarso-metatarsus, broad and 

 well excavated, including most of anterior face of sulcus with a 

 distinct ridge at level of upper third, below which the fossa has its 

 deepest excavation; inner condyle set at a slight angle so that it 

 flares outward, on the anterior side thickened toward the upper 

 end, where the inner surface, toward the intercondylar sulcus, is 

 smoothly rounded, extended as a low ridge bounding the intercon- 

 dylar sulcus around on to the dorsal face of the bone ; external face 



