376 CRETACEOUS FISHES. 
perfect about 16 inches in length ; the caudal extremity is wanting in the fossil. 
The head was small, the body cylindrical, and the scales large and smooth ; when 
seen under the microscope, they exhibit fine radiating lines as shown in the 
magnified view at fig. 11 ; the mouth was capable of great distention ; the teeth 
are minute; the dorsal fin is placed about the middle of the back. This fish is 
assigned to the family Mugilidee on the authority of M. Agassiz. 
Family HavecoIpDe1. 
Genus Osmeroides, Agassiz. 
Osmeroides Lewesiensis, Salmo Lewesiensis, Mantell R. 2. (Tab. XX XIII. fig. 4. 
Agassiz, vol. v. part 2, p. 105.) 
These beautiful fish, formerly the ornaments of Dr. Mantell’s collection, and 
now in the British Museum, are found in a more perfect state than any other 
fish in the chalk formation ; they have hitherto only been met with in the lower 
chalk of Lewes. The figured specimen of O. Lewesiensis, if entire, would mea- 
sure more than 12 inches in length. In developing these fish from the chalk 
Dr. Mantell has shown much ingenuity and perseverance, and they will ever 
remain as monuments of his anatomical knowledge and industry. 
Osmeroides crassus. 
Mr. Catt has in his collection a magnificent specimen of a head and shoulders 
of this genus, found at Southeram-pit. This fish has more resemblance to O. 
Mantelli than to O. Lewesiensis ; it was however more massive in its proportions, 
and at least double its size. The lower jaws and the intermaxillary bones were 
furnished with thick, strong, conical teeth ; the maxillary bones also carried a 
series of teeth of smaller size. This may be considered one of the finest ichthyo- 
lites that has been discovered in the chalk formation. 
Genus Tomognathus', new, Agassiz. 
The affinities of this genus are unknown; the only portions hitherto disco- 
vered have been jaws and portions of the cranium. 
Tomognathus mordaz, R. 1. (Tab. XXXV. fig. 1.) 
The lower jaws of this genus are thick and strong; the anterior portion is 
1 répos incisio, yvabos maxilla. 
