lod 
1878. ] 507 (Cope. 
Char. Specif. The external surface of the crown is marked to the apex 
with waved grooves of the enamel. The edge of the elevated cusp, which 
presents posteriorly in the maxillary teeth, constitutes the abrupt termina- 
tion of the exterior face, and is serrate by the interference of the sulci. 
The edge of the basal ledge is slightly serrate. The muzzle is rather 
elongate, and the sides of the maxillary and dentary bones are plane and 
smooth. The mandible is rather narrow, and forms a narrow wedge in 
profile outline. It rises posteriorly behind the dental line. The teeth are 
separated by intervals as wide as a tooth. 
Measurements. M. 
Monerdiamreterot Orbit Nor 1. yelmiet ve eicloee ete cfs ol OO) 
Depth of upper jaw at orbit....... Boe sista): Maka ele OLO) 
se lower jaw at front of orbit..............-... .0050 
Moumrsteethiciimiersteet.telaccccte cracinct. etree mrs cistotesats sicieke eto sia OCS. 
LE WwatLOneO tea CLO Wile sieyone sleetniers ovate styler a/eVarciey-13 10 0025 
Transverse diameter of inferior molar No. 2........... 0025 
From the sanie locality as the Diadectes sideropelicus. 
A slight modification of character is found in two imperfect crania. 
The principal character is to be seen in the teeth. The enamel of the ex- 
ternal surface of the cusp is not sulcate, but is smooth ; and the posterior 
cutting edge of the cusp is much less distinct. It is, in fact, obtuse, and 
not serrate. The orbit is large, and the front and muzzle are regularly 
decurved to the premaxillary border. The angle of the mandible is mod- 
erately prominent, and is massive and obtusely truncate. The interorbital 
region is flat in the transverse direction. 
Measurements. M. 
Length of skuli to mandibular angle...............-..,. -030 
os 2G, MMO ope So obeeon Goo Hosonuescda sé seo Alb) 
ILO OTE .O OH Otics sepenen damosaooRanedpeonboencas aliilts: 
Whadithroreinterorbitial Te StOnlcc'. «10 cass cieters vcleicierel ath velereret OOO 
Betas MCC OMMMMGee ics eer ajs wreal: sere sa.uecisvot nace rastesteea TOLU 
BOLOSAURUS RAPIDENS. Sp. noy. 
Established primarily on a tooth from the posterior or middle portion of 
the series, with which is associated another, probably from an anterior 
position in the jaw. The size is many times greater than that of the spe- 
cies of this genus already described, and it is uncertain whether the poste- 
rior tooth possesses the internal ledge characteristic of them. The anterior 
tooth does not possess it. The transverse diameter of the crown is consid- 
erably greater than the antero-posterior, and the convexity of the outer 
side is without facets. One side of the curve is flatter than the other- 
The enamel is perfectly smooth. The inner face is occupied by the surface 
of attrition of the corresponding tooth of the opposite jaw. The supposed 
anterior tooth is from another locality. Its section is similar to that of the 
present tooth, and the enamel is similarly smooth. The cutting edges are 
both smooth, and bounded by a little groove next the plane inner face. The 
