I 78 KANSAS UNIVERSITY QUARTERLY. 
responding to the megarhynchous, microrhynchous and mesarhyn.- 
chous types of Dollo.* 
The Tylosaurine begin with Liodon (7ylosaurus?) Haumurensis 
Upper Senonian of Belgium as found in the genus /ainosaurus 
Hector in the Cenomanian of New Zealand and continue to the | 
Dollo, from the Brown Phosphatic Chalk of Mesvin Cipley... In 
the interior of North America the type, so far as known, begins 
near the lower part of the Niobrara and terminates at its close or 
in the beginning of the Ft. Pierre, that is, to use the European | 
time periods, with the close of the Turonian or the beginning of 
the Senonian. Forms ascribed to this genus, the Zcodon of Cope, | 
are from the Lower Greensand or Lower Marl of New Jersey, but ; 
their positive identification is yet uncertain, if not doubtful, since 
the'only charactéristic parts, the rostrum, quadrate and limb bones 
occurrence in these beds, but hitherto nothing decisively charac- 
have never yet been found. There is nothing improbable in its | 
teristic of Zylosaurus has been found there.’ The genus Hainosaurus 
C o 
is clearly of the Zylosaurus type. In fact the two genera are so 
nearly related that decisive distinctional characters are not yet 
forthcoming, unless they be found in the paddles. 
The Platecarpine have avery similar distribution. Beginning | 
in the Cenomanian of New Zealand, in Zaniwhasaurus, if the de- 
posits of New Zealand are really cotemporaneous with this epoch 
in Europe, they terminate in the closely allied Plioplatecarpus Dollo 
from the Lower Mestrichtian of Belgium. In North America the | 
species upon which the genus P/adecarpus has been chiefly based | 
are known nowhere outside of Kansas and Colorado, and are here my 
restricted exclusively to the Niobrara. The type species of this : 
genus, ?. dympaniticus Cope, is from Mississippi and is in all prob- } 
ability congeneric with the Kansas species, but this has not yet been 
satisfactorily proven, though it certainly belongs in the Platecar- 
pine. 
From the Ft. Pierre only one species can be referred to this 
group, and this with doubt. Arachysaurus described by myself in 
the last number of this Quarrerty may belong here, but I believe 
that its affinities are more close with the Mosasaurine. It is cer- | 
tainly closely related to Prognathosaurus Dollo,+ from the Upper ‘ 
Senonian of Belgium, and I should have had little hesitancy in | 
identifying it with that genus had not Dollo stated that the chevrons | 
are free in Prognathosaurus. it | 
: st ‘ 
*Mem. Soc. Belg. de Geol., iv, 163, 1890, 
+Mem. Soc, Belg. de Geol., iii, 198, 1889. [ 
‘Mem, Soc. Belg. de Geol., iv, 163, 1890. { 
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