I903-] 



Hay, North American Cretaceous Fishes. 



59 



cleithrum; for the lower end is missing (Fig. 43). On the 

 inside of the cleithrum there is a precoracoid which ascends 

 from the coracoid three-fifths the distance to 

 the upper end of the cleithrum. This pre- 

 coracoid, which is like that of Portheus, was 

 doubtless regarded by Cope as the coracoid. 

 There are two large convex surfaces for articu- 

 lation with the fin, the uppermost with the 

 large first ray, the lowermost with the first 

 baseost. On a level with the latter, but more 

 mesiad, are two pits, undoubtedly for the 

 reception of the next two baseosts. The 

 proper interpretation of these parts is made dfctfs ^mJtld'nt'a- 

 easy by comparison with the shoulder girdle x i "/t'ciekhmm j 



r i 1 art. s.. articular sur- 



Ot a tarpon or salmon. face fJr fin ray. 



Gillicus Hay. 



The type of this genus is Cope's Portheus arciiatns, later 

 called by him Ichthyodectcs arcuatns. Dr. A. S. Woodward 

 (Cat. Foss. Fishes, IV, 1901, p. loi, pi. viii) has recently 

 described a second species, Gillicus serridens, from the Albian 

 epoch, Kent, England, under the name Ichthyodectes serridens. 

 It differs in having the anterior mandibular teeth relatively 

 larger. The members of this genus are well characterized by 

 the falcate maxillae, the reduced dentition, and the thin skull 

 bones. 



PACHYRHIZODONTID.^. 



Pachyrhizodus Agassiz. 



Cope originally made this genus the type of the family 

 Pachyrhizodontidae (Proc. Amer. Philos. Soc, XII, 1872, p. 

 343). Later he placed it in the family Stratodontidae (Vert. 

 Cret. Form. West, 1875, p. 219). Loomis and Stewart regard 

 the relationships of the genus to be with the Salmonidae. 

 Dr. A. S. Woodward in his latest volume places the genus 

 in the Elopidse. To the present writer it seems best to retain 

 it and its related genera in a special family as Cope originally 

 did, until more is known regarding the anatomy. 



