a 
72 FIELD CoLuMBIAN MusruM—GEovocy, VoL. Il. 
POLYCOTYLUS ISCHIADICUS; N.7SBi 
/ 
I give this name provisionally to a species from the Niobrara 
Cretaceous of western Kansas, represented by a number of bones in — 
the University of Kansas Museum, the most characteristic of which 
are shown in Pls. X and. XXVI. There’ is no assurance what- 
ever, however, that they belong in this genus; on the other hand they 
may belong with the type species, P. latipinnis, or they may belong 
to. some unrecognized genus. The ischia, it is seen, differ very 
markedly from the corresponding bones of Dolichorhynchops osborniin - 
the shorter length of the symphysial portion, in the greater breadth of 
the neck, and in the smaller extent of the cartilaginous rim posteri- 
orly. The bones are also more massive and the face for the ilium is 
larger. The ila also are materially different, in the greater expan- 
sion proximally, and in the absence of the lateral angular face dis- 
tally. They have a somewhat curved neck, with a rounded head 
showing a cartilaginous surface. The transverse processes of the 
sacral vertebra are more massive than in that species, with a consid- 
erable expansion proximally, a cylindrical shaft and a terminal, some- 
what oblique face for articulation with the illum. The somewhat 
compressed sacral vertebra is shown from its ventral. surface. 
A specimen from the Niobrara in the Kansas Museum, comprising 
a number of caudal vertebre and a portion of the pelvis, I refer with 
much more assurance to P. /atipinnis Cope. The vertebre differ very 
materially from the present, and the probability is, therefore, that ?. 
ischiadicus 1s not a Synonym of P. datipinats. 
PLESIOSAURUS GOULDII. 

Plesiosaurus gouldit Williston, Kansas Univ. Quart. vi, p. 57, Jan. 1897. 
Among the material collected in the Lower Cretaceous shales of 
Clark county, Kansas, by Prof. C. N. Gould, and now preserved in 
the museum of the University of Kansas, are the remains of at least 
three different forms of Plesiosaurs, all, however, represented by 
rather incomplete material. Portions of one of these forms (/P/eszo- 
saurus mudget (?) Cr.) are figured elsewhere in this paper; another 

