Page 22 - maxson1928

If.

From M.iolabis transmontanus, however, it differs in some important

details The dentition seems more primitive. The dental series is shorter.

Reduction of premolars is not quite so marked. Premolar one is more strongly

two-rooted for in M. tra.nsmontanus the roots a.re separate only at the extremi tie~.

The premolar series is not directed inward at an angle from the molar

series but both form a comparatively straight chain. In M. transmontanus

the premolar-molar ratio shows a relatively greater development of molars

than is the case in the new species. Perhaps the most important differences

are in the diastemata. Although uhe skull itself is smaller the diastemata

behind I~ and c.! re spec ti vely are longer than those L1 M. transmontanus.
l 2
On the other hand, the diastema between P- a.nd P- is much shorter {approx. 15mml~

These distinctions are regarded as sufficient to separate the Mint

Canyon form from hitherto defined species. For this type the name Miolabis

californicus is suggested.

Comparative Measurements

M. transmontanus M. ca.Lfornicus Auchenia llama
{No. 30046 u.c.)

l
Length of skull ------- &300 mm. --------- a250 mm 280 mm.

Width behind. orbit a.100 142
3
Dentition I to M- 257 ---------- &147 ------- 172

Length p~ to w!. 92 ---------- 79 --------- 70
pg p!
Length to 35 ----------- 31 --------- 17
l
Length M- to M~ -----···- 57 ----------- 48 -------- 53
Diastema I~ to c! 6 ---------- 9 -------- 17

p1
Dia.stema c! to 11 ---- ------- 13 --------
l 43
Diastema P- to p~ ------ 20 ------------ a.5 ------ -

l Measurement computed from proportion of skull relative to skull

of Protolabis montanu.s.