. Bulletin. Natural history; Natuurlijke historie. 44 PEABODY MUSEUM BULLETIN 28 arm of the protoconid. It is closer to Ph. andrewsi in the first three characters and to Ph. lavocati in the last. It seems very probable that it represents a struc- tural stage of Phiomys leading toward Paraphiomys. However, since all the material of this species is from Quarry G whereas that of the equally Paraphiomys- like Ph. lavocati is from the earlier beds of Quarry E, and since a fully differen- tiated species of Paraphiomys is present in Quarry I, Ph. paraphiomyoides could only represent a late survival o
. Bulletin. Natural history; Natuurlijke historie. 44 PEABODY MUSEUM BULLETIN 28 arm of the protoconid. It is closer to Ph. andrewsi in the first three characters and to Ph. lavocati in the last. It seems very probable that it represents a struc- tural stage of Phiomys leading toward Paraphiomys. However, since all the material of this species is from Quarry G whereas that of the equally Paraphiomys- like Ph. lavocati is from the earlier beds of Quarry E, and since a fully differen- tiated species of Paraphiomys is present in Quarry I, Ph. paraphiomyoides could only represent a late survival of the transitional stock. Phiomys aff. paraphiomyoides Figure 4 Description. Four lower jaws, YPM 21292-94 and 21366, from the upper level (Quarry I) are tentatively identified as Ph. aff. paraphiomyoides. In molar pattern they are indistinguishable from Ph. paraphiomyoides (compare figs. 3 A and 4 A), but they are of considerably larger size (compare Tables 2 and 3). The jaws are slender, as in Ph. paraphiomyoides (compare figs. 3 C and G with 4 B), but differ from all other specimens referred to Phiomys in the extremely high position of the mental foramen on the jaw. The foramen is just below and in front of the anterior root of P4 (fig. 4 B).. FIGURE 4. Jaws and teeth of Phiomys aff. paraphiomyoides, YPM 21294. A. left dPi-Mi, X 10. B. Lateral view of lower jaw, x 5. The pattern of dP4 is slightly more progressive in the material from Quarry I. In one of the two specimens (YPM 21293) the anteroconid is connected to the anterior arm of the protoconid, and in the other (YPM 21294, fig. 4 A) the an- teroconid has united with both the protoconid and metaconid and forms the principal connection between these two cusps, with the metalophid greatly re- duced. In the molars the pattern seems to be identical with that in the type of Ph. paraphiomyoides (fig. 3 A) with no posterior arm of the protoconid on M^ and a very slight one on M^. The enamel seems to be proportionately thicker
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