6 Dr. Buckland on the Fossil Beaks of four extinct Species 
superior and inferior maxillary bones of the same species 
exhibit rugous surfaces of attachment, from which their horny 
coverings have been removed. The same marks of attach- 
ment are seen in the lower jaw-bones of the Chimera Agassizit 
and Chimera Mantellii. The horny investment of all these 
bones has evidently fallen off and perished, like the horny 
covering which separates readily from the bony beak of Tur- 
tles, and which is rarely, if ever, found with the bones of 
fossil Testudinata. 
The genus Chimera is one of the most remarkable among 
living fishes, as a link in the family of Chondroptérygiens. 
The fact of the existence of many fossil species of this curious 
genus (and some of these much larger than the single known 
existing species) in such early periods as those of the Oolitic 
and Cretaceous formations leads to important considerations 
in Physiology. 
Professor Agassiz has at my request prepared the following 
description of the four fossil species which form the subject of 
this communication. Further details and figures will be pub- 
lished by him in the eighth number of his Pozssons Fossiles. 
Note by Professor Agassiz. 
The discovery of the genus Chimera among. fossil fishes 
is one of the most interesting and unexpected. 
Recent Chimeras are very little known, and have been ar- 
ranged in the order of cartilaginous fishes, but their organi- 
zation, and especially the structure of their skeleton, has not 
been sufficiently studied. Dr. Buckland’s discovery will draw 
the attention of Ichthyologists in a particular manner to this 
singular family. ‘The four fossil species about to be enumer- 
ated differ essentially from each other, and are considerably 
larger than the living. Unfortunately the fossil fragments 
which we now possess are far from being complete; only the 
jaws of these curious fishes have hitherto been discovered, and 
principally the lower jaws. 
In the Portland species, the Chimera Townsendii, which is 
the largest, the inferior maxillary is very large, short, and 
proportionally much thicker, the groove of the symphysis of 
its two branches shallower, and the cavity of the dental edge 
broader than in the other species; its exterior surface is con- 
vex and furrowed longitudinally with shallow wrinkles. The 
intermaxillary bone is much bent. 
In the Chimera Egertonii the inferior maxillary is short 
and flat; its snout is truncated, and in proportion very large ; 
the cavity of the dental edge is very wide and the groove of its 
symphysis very deep; the intermaxillary is much bent, and 
