304 University Geological Survey of Kansas. 



Cope describes his specimen with the posterior teeth slightly 

 larger than the anterior, which seems rather remarkable for 

 this family. The posterior extremity of the maxilla shows this 

 portion to be upturned, as Cope has indicated in his figure. 00 



The quadrate has its condyle twisted forward until the face 

 is almost in line with the anterior border. The upper border is 

 straight and the groove for the S3^mplectic narrow. The cerato- 

 hyal is concave posteriorly, convex and contracted in width an- 

 teriorly. 



Dentary : Length of alveolar border 101 mm. 



Length of symphysis 43 " 



Length of crown, anterior 7 " 



Number of teeth in one centimeter 3 



This specimen was obtained from the Niobrara Cretaceous, 

 five miles northeast of Russell Springs, Logan county, Kansas, 

 by the geological expedition of the summer of 1898. 



GILLICUS. 



Hay, Amer. Jour. Sci., vol. VI (1898), p. 320. 



The genus Gillicus has recently been proposed by Professor 

 Hay, to include Ichthyodectes arcuatus Cope and 7. polymicrodus 

 Crook, which differ materially from the other species of Ichthyo- 

 dectes, especially in the form of the teeth and tooth-bearing 

 elements. Before entering into the description of this interest- 

 ing form, it will be well to give a short resume of the discus- 

 sion which has taken place over these two species, as is also 

 done at some length by Professor Hay. 61 



In 1875 Professor Cope first described his Portheus arcuatus 

 from some very imperfect remains from the yellow chalk of the 

 Solomon river, Kansas. It is difficult to say just why Professor 

 Cope first referred this to 'Xiphactinus (Portheus) , as the dental 

 and other characters are entirely different from that genus. 

 Cope evidently discovered his mistake soon afterward, as he 

 refers it to Ichthyodectes in 1877. ° 2 Nothing more was done with 

 this species until 1892, when Doctor Crook published his paper 

 entitled " Uber einige fossile Knochenfische aus der mitteleren 



60. Cret. Vert. West, pi. XLVI, fig. 1. 62. Proc. Am. Phil. Soc, XVII, p. 177. 



61. 1. c, pp. 228, 229. 



