22 The A iiicricfiii fjcohx/isf. July. lJ'9r> 
The mandible is nearly straight and meets its fellow of the 
opposite side at a very acute angle. The symph3'sis was not 
terminal but was overhung, as will be shown later, by the 
forward projection of the maxillar3\ 
The maxillary also consists of a thin plate of bone of a 
similar nature and appearance to that of the numdible with 
which it unites posteriori}^ by a condyle fitting into a fossa or 
socket in the latter. The hinder part of this bone is in good 
condition but its anterior portion is badly crushed and dis- 
placed except along the edge that carried the teeth where it 
is well preserved. It bears the same style of ornamentation 
as the mandible already described and on its lower edge, be- 
tween the condyle and the teeth, stood a row of fine, sharp 
denticles facing those already mentioned in the lower jaw. In 
front of these are six conical teeth, and three others can be 
supplied from analogy with the opposite maxillary, making 
nine in all. These in no wise differ from their antagonists in 
the numdible already spoken of. But in front of them and 
apparentl}^ rather in front also of the foremost of the lower 
teeth stand two very much larger and stronger than the rest. 
They are unfortunately somewhat forced out of place bj' the 
compression to which the fossil has been subjected, but they^ 
apparently inclined backward as well as downward, thus 
gaining additional prehensile power. 
All the teeth are perfectly simple and show no sign of lat- 
eral denticles of any kiiul and of course no successional teeth 
are present. 
The maxillary bones are firmly united in front and form a 
sharp beak or snout, jjrojecting an inch beyond the above 
mentioned large teeth. All the rest of the head has been so 
crushed as to be quite unrecognizable, though some fragments 
of comparatively thick plates indicate the existence of an os- 
seous cranium. 
Along the lower edge of the mandible is a series of plates 
which were regarded by Dr. Newberry as representing the 
branchiostcgal rays. He remarks "branchiostegal rays nu- 
merous" iii his decription of the species. They are perhaps 
more correctly described by Mr. A. S. Woodward in his cata- 
logue as a paired series of transversel}' elongated rays deyel- 
