memoir upon the genus 
-.1 . whether the sustentacular filcet is continuous with the inferior 
or not. these facets in continuity. The 
iu oo„*lder„blc.-, i.« plane 
iiilenor facet la ra a r ' >= the cuhoid facet. The latter is narrow and deep 
!i;"!r.Lv. irln-nl • L Lrlace ie concave, and only the „pi>er part of its internal 
kl-r i. irancat.al l.v tin. inferior facet. In Z. latueps the lower lx,rdcr o the 
mill fa.a-t i. l.arn.w and roun.l ; in the other related fonns it is fiat. A hhnlo 
ciilcaiieiiiu facet is not well marked. , i + c d . 
lslraf:alus.— \'\w form of the astragalus closely resembles that of P minor , 
i, i, l,„„ «a,l narrow with it. distal lK,rlion well constrieted off. The troch ear aur- 
fu.v is sliullow. 'I'he facets of the inferior surface are large, the sustentaculum and 
inferior U-ing continuous. The ectal facet is not as deep as in P. minor, but it lias 
the same pi-iiend form. Tlie sustentaculum is long and narrow and its plane is 
not ns <dili(|ne as in llie smaller species Palceosyops. The distal continuity of the 
sHstcnincidnni witli theculHiid facet is not interrupted by a ridge as in P. minor. The 
inferior fa<-el reaches alsiut half way across the anterior border of the bone, liefore 
C«mlesciiig with tlie mistentaculuin. * The cuboidal facet is long and nari-ower than 
in 1\ minor ; its plnne is nearly parallel with the navicular face of the astragalus, 
thus differing wiilely from that of /h minor Avhere the cuhoid lacet forms a sharp 
angle with the anterior face of the Ixmc. The form of the navicular facet is not 
so strongly triangular in out lint* ami is moiv elongated transversely than in P. minor . 
'file more liori/oiital jMisitioii of the sustentaciihir facet produces only a sliglit angle 
on the internal Isirtler of this face. The characters given above for the astragalus 
of /.. laticef>s approach closely tlmse found in the larger species of Ifyrachyus, hut 
its large size excludes it fntm that genus. 
Cnncifortns . — 'flic eet<H-nneiforin is wanting in tliispes; it is probably much 
higher ami narrower than in /’. pa/ndosus, and appi'oaclies more nearly tlie diameter 
tif this Isnie in //yrnchyns. 'I'lie inesocuneiform is preserved; it is a very deep 
Unie with a sinidl antt>rior lace ; its articular surfaces are concave antero-posteriorlv. 
CiiSoid. 1 lie culKiid is still another tarsal bone of this species very closely 
n'M'mhling that of Hyrachyus, although it is rather more rectangular and shorter 
than ill that g,*mis. Its external iKirder is .straight and not concave as in Hyrachyus. 
The tiilH*n.sity of the eiilx.iil is wanting in this specimen, but its position was 
|.n.l.nl.ly very similar to that of Hyrachyus. The astragalar facet is large 
ami IS aol M.,,nn,t,*il from the plane of the calcaneal fiicet as in P. minor. The 
facets for the navieiihir and eetiK'imeiform e.xtend more than halfacro.ss the inh*nial 
facH* o the lK,ne ; they im* separate.! by a ridge, and the posterior part of the navi- 
,1 st«l artilnr I '■‘T posterior internal border of the bone. Tlie 
.hsn Urtieula lac* ol the ouIh... is slightly concave, and is much smaller tlian in 
/.nin,^. I he uppr .surface of the cuboid m excavated- 
.n tins s,H.i,.s. the contrary this surface is perfectly iat the dital l^e on . 
