1881.] 493 
[Cope. 
rior molars, if they are properly identified; and in the superior molars. 
The anterior transverse crest of that genus is represented in Protogonia, 
but not the posterior. This is replaced by a low ridge running across the 
course it pursues in Hyracotherium. The posterior median tubercle is also 
not found in the latter genus. Protogonia differs from Limnohyus in the 
subconic character of the external lobes of the superior molars. If the tu- 
bercles, excepting the posterior inner, should be converted into crescents, 
the genus Meniscotherium would be produced. 
Char. Specif. Probably two specimens; one supporting three superior 
molars ; the other including damaged superior molars and the last two in- 
ferior molars. The animal was about the size of the red fox. The exter- 
nal cusp of the fourth superior premolar is flattened externally, and has a 
small lobe on its posterior edge. The inner tubercle is conic and is sepa- 
rated by a tubercle from the anterior base of the external. True molars 
without external ridges. The external cusps of the true molars are lentic- 
ular in section. The posterior inner cusp is in nearly the same antero- 
posterior line with the anterior, its section about equaling that of the 
intermediate cusps. The first and second molars have an external, an 
anterior and posterior, but no internal, basal cingula. The enamel is 
somewhat wrinkled where not worn. 
The heel of the last inferior true molar is elevated, and its worn surface 
forms the extended posterior branch of the posterior V. The posterior 
edge of the penultimate molar is elevated and curved forwards on the in. 
ner side of the crown. The anterior cusp forming the angle of the V of 
this tooth, is higher than the posterior angular cusp, but the anterior limb 
descends rapidly as in Coryphodon. A weak antero-external, and postero- 
external cingula. Enamel wrinkled where not worn. 
Measurements. M. 
No. 1. 
Length of bases of three superior molars.........-.... 025 
, : anteroposterior....... .0066 
Diameters of superior P-m. IV ; transverse .....-...-- .0086 
, . anteroposterior....... .0085 
Diameters of superior M. I ; transverse ........... .O11 
3 anteroposterior....... .009 
Diameters superior M. IT ; transverse .........6 011 
No. 2. 
Length of bases of last two inferior molars............ 0225 
. f last inferi 1 anteroposterior....... .0114 
Disiiniets pk ansiterener so ; transverse. .....----- -0066 
: ‘ : anteroposterior....... -0112 
Diameters of inferior M. IT ; transverse ........-.. .0080 
~ Depth of ramus at M. II...........+.+- Patera orale tiss 0240 
Thickness “ ‘6 fsa ccee cence ccc ce rece ereeeeee 0110 
MENISCOTHERIUM TERRARUBR&, sp. nov. My specimens of this species 
embrace the dentition of several individuals. 
