Stewart.] Cretaceous Fishes. 295 



The arrangement is three large, two small, one large, and the 

 twelve or thirteen medium and small. Many of the alveoli are 

 empty, so the size of these teeth has to be estimated ; the num- 

 ber of these, however, no doubt varies with the individual. 

 The coronoid process is but poorly developed. The dermar- 

 ticular invades the dentary but little externally, and the cotyloid 

 process of this bone is not so well developed as in X. audax. 



Length of alveolar border 215 mm. 



Depth of coronoid process 118 " 



Length of symphysis 105 " 



Depth of bone just back of symphysis 100 " 



Length of bone from cotylus 270 " 



There are fragments of several other bones, among which 

 are the ethmoid, a prefrontal and palatine, and several verte- 

 bra 4 . The ethmoid is acutely pointed anteriorly, and the pos- 

 terior suture is very dentate. The prefrontals are small, as are 

 also the malleolar portions of the palatines. The external 

 tuberosities of the latter are not so prominent as in X. audax. 

 The vertebra' do not seem to differ materially from the species 



mentioned. 



ICHTHYODECTES. 



Cope, Proc. Am. Phil. Soc. 1870, p. 536. 



This genus is so closely related to Xiphactinus that it does not 

 need to be characterized, beyond pointing out some of the prin- 

 cipal differences between the two forms. The teeth are more 

 regular in size and never reach the enormous development of 

 those in Xipkactinus. They are cylindrical in cross-section and 

 are usually directed slightly inward at the apices. 



As indicated by the size and dentition, this genus was much 



less ferocious than the form mentioned above, which no doubt 



preyed upon them to a great extent. The known American 



species, all from the Niobrara Cretaceous, Kansas, are : 



Ichthyodectes ririnidt* Cope. Ichthyodectes goodeanus Cope. 



Ichthyodectes ctenodon Cope. Ichthyodectes acanthicus Cope. 



Ichthyodectes hamatus Cope. Tchthyodectes pernicosus Cope. 



Ichthyodectes prognathus Cope. Ichthyodectes emeritus Hay. 

 Ichthyodectes multidentatus Cope. 



During the past summer, while collecting in the Fort Pierre 

 group, at Lisbon, Logan county, Kansas, I discovered a string 



