462 
THE STEUCTURE AND RELATIONSHIPS OF ANCODUS. 
mens display several interesting constant difi'erences from those of Europe, as figured 
in the works of Kowalevsky and Filhol. The most important specimen comprises 
the skull and lower jaws with the greater part of the skeleton of an old individual 
which maybe referred to the A. brac/iyrhytichus oi Osborn and Wortinan, though 
there are some differences, perhaps sexual, from the type of that species. 
I. TH15 DENTITION. 
The dentition differs but little from that of the European species from the 
Oligocene of Ronzon and Hempstead, and the formula is the same. Osborn and 
Wortman report that in their specimen of A. amerua7ms the first upper preinolar 
is absent, but it remains to be determined whether this is more than an individual 
character. 
A. Uppti' Jaw . — The incisors are large, of hastate shajie and nearly uniform 
size. Their arrangement is most like that of A. leptorhy 7 ichus, the median pair 
separated from each other by a considerable interval and presenting forward, the 
second and third nearly at right angles to the first, and presenting laterally. In A. 
americmius the incisors are implanted quite closely together, while in A. b 7 'achy- 
rhynchus VciG\ are spaced well apart. The canine succeeds the lateral incisor alter 
a short diastema, as is also the case in A. velamms, not as in A. Aymardi or A. lep- 
torhynchus, after a long interval. The crown is small, not much exceeding those 
of the incisors, but longer, more slender and pointed. It is much smaller tlian the 
peat, curved, tusk-hke canine of A. leptorhynchiis, though not so much rediu;e<l as 
in the other two species of Ronzon, in which, according to Filhol, it has th(> form 
of p. tliongl, dist.nctly smaller. How Ihr 11, e .liirere.icos betrvee,. tlio suppose, I 
.species ol Rouzoii, rogonliiig llie fern, and size of tlie eiiiiiin.s. ai-e sexual, eainiot at 
pi-eseal be defer,,,,,, ed, tboagl, it is sig„ific,,„„ ,l,a, of ,|,e s,,,.,-!,,,,.,,., so far 
il" I'yo “>"',08 comparable ii, size to tl,o.se of A. Upiorl,y„c/ms. 
two '.’''“y*’'”’*''™ 1 '-e,-,. 8, nail, si.ople tool!,, i.aplaoled by- 
two doergmg laogs and will, a coinpresse,! conical c,-ow„. Its posili,,,, is soblect 
o soiae v.irial,,,,, „, die different specimens of A. brachyrhyuchm : in the type it 
these, and especiallv in A J f ["''"'I of the Ronzon species. In 
rated. In A. a 77 ie 7 'icami^ wE 1 ' species pi and p: are also widely sepa- 
caniues and the nremola.l I?’’ 'j^^t'veen the 
gulum than is usual in them It is of prominent cin- 
intotnal dngnlm.,, im f™! !’ witl, st,-„„.dy developed 
It may be sep.arated from lliat tooth bv » 1 “y*’ “ '"V ho in contact wit I, ]>?, or 
extended than in Aymardi TP T, ■ however, is much less 
■ >n.a,d,. The th.rd , wen, oh,, i, like the second, hot larger 
