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 alveole, 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. Itis perhaps the articular face for the ex- 
tremity of the vomer. As compared with the other species, this one is 
characterized by the lateral 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 alveole 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. nitida, it is sculptured with ridges. Length preserved, auterior to 
dental alveole, 0.045; transverse diameter in front of alveoli 07.025; 
vertical diameter 0.020. This species may be called L. ziphioides, from 
the Ziphius-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 2’. nitida, and which were 
supposed at that time to belong to a species of Sawrocephalus. A muz- 
zle, perhaps of the same species, was regarded as a Sword-fish, which was 
‘called Xiphias dixonii by Agassiz. It should be now termed Zrisichthe 
dixont. 
