COPE ON THE GENUS ERISICHTHE. 823 



is quite peculiar. Its shaft is depressed, with a strongly convex inferior 

 surface and a slightly convex superior surface, the two separated by an 

 obtuse angular border. Behind the alveolae, the inferior surface is nar- 

 rowed by a strong lateral contraction, in which the superior surface 

 shares in a slight degree. The latter is continued in a prominent border. 

 The inferior surface is divided by an angular depression, the apex of 

 which is directed forward. It is perhaps the articular face for the ex- 

 tremity of the vomer. As compared with the other species, this one is 

 characterized by the latsral longitudinal concavity at the base, which 

 appears to be an anterior prolongation of the grooves for the premaxillary 

 bones. The small size and anterior position of the alveolae of the 

 basal pair of teeth is also a marked character. The superior surface of 

 the skull at the base of the beak is apparently unworn ; it is smooth. 

 In E. 7iitida, it is sculptured with ridges. Length preserved, anterior to 

 dental alveolfe, 0™.045 ; transverse diameter in front of alveoli 0'".025 ; 

 vertical diameter 0™.020. This species may be called U. ziphioides, from 

 the Z//>M?(s-like form of the beak. 



A fourth species has been found in England, and figured by Dixon in 

 the " Geology of Sussex". The portions represented in this work are 

 the mandibles, which resemble those of the E. nitlda, and which were 

 supposed at that time to belong to a species of Saurocephalus. A muz- 

 zle, perhaps of the same species, was regarded as a Sword-fish, which was 

 called Xlphias dixonii by Agassiz. It should be now termed Erisichthe 

 dlvoni. 



