72 Field Columbian Museum — Geology, Vol. II. 



POLYCOTYLUS ISCHIAD1CUS, N. SP. 



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 Pis. 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 Dolicharhynchops osbornixn 

 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 ilia 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 vertebrae 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 ilium. 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 vertebrae and a portion of the pelvis, I refer with 

 much more assurance to P. latipinriis Cope. The vertebrae differ very 

 materially from the present, and the probability is, therefore, that P. 

 ischiadicus is not a synonym of P. latipinnis. 



PLESIOSAURUS GOULD1I. 



Plesiosaurus ^w/V/VWilliston, 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 {Pltsio- 

 saurus mudgei (/) Cr.) are figured elsewhere in this paper; another 



