; APPENDIX. 
Art. LI.—On the Odontornithes, or Birds with Teeth; by Prof. 
O. C. MarsH. With plates IX and X. 
which have already been described by the writer. @ most 
mportant of these remains, so far as now known, are the 
Odontornithes, or birds with teeth, and it is the object of the 
present communication to give some of the more marked 
characters of this group, reserving the full description for a 
memoir now in course of preparation. 
The first species of birds in which teeth were detected was 
Ichthyornis dispar Marsh, described in 1872.* Fortunately the 
type specimen of this remarkable species was in excellent 
and pointed, and all are directed more or less backward. 
€ crowns are covered with nearly smooth enamel. The 
maxillary. teeth appear to have been numerous, and essentially 
the same as those in the mandible. Whether the premaxillary 
bones Supported teeth, or were covered with a horny beak can- 
hot be determined from the present specimen. 
* This Journal, vol. iv, p. 344, and vol. v, p. 74. 
