1898.] Osborn^ Evolution of the Amblypoda. Parti. 20\ 



tinct from the raetacone ; the ectoloph thus does not form a con- 

 tinuous crest as in the supposed type. The ])arietal protuber- 

 ances or rudimentary horns Fa.H, are less pronounced but 

 equally rugose ; the premaxillary symphysial borders are extensive 

 although without contact ; the incisors are equal in size, ii and 

 i 3 being fully as large as i 2 in both jaws. This is therefore a 

 smaller and perhaps more primitive type than either C. lohatus 

 or C. testis, although skull No. 275 is definitely recorded by 

 Wortman from the Buffalo Basin, the highest true Wasatch level. 



Unfortunately the characteristic last lower molar is missing in 

 the cotype ; the series pm i-m 2 measure 122 mm. The lower 

 jaws of C. elepltaiitopiis are also represented either by Cope's 

 C. obliqims or by his C. latidcns (see below). The former is more 

 probably the case for the following reason. According to the 

 ratio of upper and lower teeth established in the C. testis jaws 

 (see Table, p. 199, No. 3829), the lower grinders in C. clephantopiis 

 should measure 167 mm. The type lower molar of C. obliquus ap- 

 proximately agrees with this size (see Table, p. 199) and character. 

 The last lower molar of C. obIi(/iais agrees closely with that of the 

 supposed type of C. elephantopus. We may therefore consider the 

 greater or less development of the entoconid 2, which these 

 molars present, as variations similar to those which we have ob- 

 served in the other species of this series, namely, C. testis and 

 C. lobatiis. 



No complete jaw is nearer this size than No. 4321 (Am. Mus., 

 Cope Coll.), in which the lower grinders measure 172 mm. ; this 

 specimen is also significant because the last inferior molar on the 

 right side agrees in form with C. ciispidatiis {i.e., entoconid 2, dis- 

 tinct), while the same tooth on the left side agrees with C. obliquus 

 {i.e., entoconid 2, obsolete). Another proof of the variability of 

 these cusps. This jaw, however, may l:)elong to a small female of 

 C. testis. 



Incert.e Sedis. 



21. Coryphodon repandus Cope. 



Type, No. 4309, Am. Mus., Cope Coll. Superior and inferior molars mJ, m^, 

 m^, nig. Symphysis of lower jaws. Size=C. testis, male. Loc, Big Horn, 

 Wyoming. 



