184 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
of the river from Leavenworth, Kansas, near Weston, in Platte County, Mis- 
souril. “The name by which it may be designated has reference to the inter- 
mediate characters which it displays between Orodus and Campodus. The 
coronal surface is elevated into a median prominence, and is marked with the 
longitudinal and transverse ridges which are so conspicuous a feature of Orodus, 
but at the same time the outer coronal margin, which at the most is only 
faintly crenulated in other species of Orodus, is here differentiated after the 
manner of Campodus. It is obvious that the two genera are very closely 
related, but the characters by which they may be provisionally distinguished 
appear to warrant their separation, at least until such time as we shall have 
obtained a more perfect knowledge of the arrangement of the dentition in both 
forms. 
Formation and Locality. — Missourian; Missouri River Valley. 
CAMPODUS be Konincx. 
Campodus variabilis (Newserry and WorTHEn). 
(Plate 1, Fig. 1; Plate 2, Figs. 15, 16.) 
j 
1870. Lophodus variabilis Newberry and Worthen, Pal. Illinois, Vol. IV., p. 361, 
Pl. -TV.; Bigs: 4,.5, 11: 
1875. Agassizodus variabilis St. John and Worthen, Op. cit. Vol. VI., p. 318, Pl, 
VIIL., Figs. 1-22. 
1883. Agassizodus variabilis M. Lohest, Ann. Soc. Geol. Belg., Vol. XI., p. 305, 
Text-figs. 1, 3. 
1901. Campodus variabilis C. R. Eastman, Science, Vol. XIV., p. 795. 
1902. Campodus variabilis C. R. Eastman, Geol. Mag. (4), Vol. IX., p. 148, PI. 
VAIT., Fig. 1. 
1902. Campodus variabilis C. R. Eastman, Bull. Mus. Comp. Zool., Vol. XXXIX., 
p. 6), Piss tT, Ply. Bigs. 
Detached teeth of this species are of not infrequent occurrence in the Mis- 
sourian of Iowa, Kansas, and Nebraska, and in two or three instances a large 
part of the dentition has been found in natural association. The complete 
dentition of one jaw (presumably the lower) is known from a series of inter- 
esting specimens, the most important of which was first described by St. John 
and Worthen in Volume VI. of the Palaeontology of Illinois, and has been 
since re-investigated by Max Lohest and the present writer. _ The original of 
this magnificent specimen is now preserved in the private collection of Mr. 
Frank Springer, and casts made from it by St. John in 1874 are in existence 
in a number of museums. One of these plaster casts was utilized in the 
construction of the model shown in Plate 1, which represents the restored 
dentition, the symphysial series in front being photographed from an actual 
specimen belonging to the Museum of Nebraska State University. 
The nearly complete ramus of the lower jaw described by St. John and 
