Davis — On the Fossil Fish of the Cretaceous Formations of Scandinavia. 425 



The head is large, and absorbs quite two-fifths of the entire length. The facial 

 contour forms a prominent feature. The body of the fish rapidly diminishes in size 

 towards the tail. It is to be regretted that no specimen is' sufficiently well 

 preserved to exhibit the entire form of the fish ; but a more or less complete idea 

 can be obtained by comparing the several specimens, and taking the aggregate 

 result. (PL XLVi., fig. 7.) 



The head is produced anteriorly, and terminates in a protruding snout ; the pos- 

 terior margin, formed by the operculum and a thin median bone extending from the 

 supra-occipital region forwards, is more or less circular in outline. The orbit is 

 situated in the posterior moiety of the head, and is somewhat high; it is large 

 and encircled by bones. In front of the orbit a large but thin bone may be 

 distinguished, which represents the pre-orbital ; its posterior boundary is formed 

 by the margin of the pre- operculum. A straight bone, probably the para-sphenoid, 

 extends across the base of the orbit. The maxilla is long and somewhat slender, 

 and is divided by an oblique suture from the pre-maxillary. The mandible 

 is large, high in front, diminishing in size backwards, and extending to a 

 position beneath the orbit, where it is articulated with the quadrate. No teeth 

 can be distinguished on any of the specimens, either on the upper or lower jaws. 

 The inter-orbital bones are not well preserved on any of the examples ; but 

 fragmentary outlines exist which indicate that the frontal and occipital bones are 

 produced, and form a thin median bony crest, extending above the orbit back- 

 wards. The operculum consists of four elements : the pre-operculum is a 

 triangular bone, with a concave anterior margin, pointed above, and rounded 

 below ; deep ridges extend from the pointed upper margin, and radiate towards 

 the circular inferior margin. Behind and above the pre-operculum is the 

 operculum ; it is rounded behind, and channels radiate over its surface from the 

 upper anterior margin, where it joins to the pre-operculum. It is the largest of 

 the opercular bones. The sub-operculum is a long bone, extending parallel with 

 the operculum, and situated immediately behind it. The inter-operculum is also 

 long and narrow, extending from the sub-operculum to the anterior extremity of 

 the pre-operculum. Other bones of the head may be distinguished, but not with 

 sufficient distinctness to be readily identified. 



The vertebral column consists of thirty vertebrae, of which ten are abdominal, 

 and the remainder caudal. The vertebra nearest the head are equal in height to 

 the length, but towards the tail they become gradually narrower, so that the 

 height is greater than the length. The centra are biconcave, and the median 

 external surface is much constricted. The apophyses of the vertebrae are strong 

 and afford attachment to haemal and neural spines, the former of great length. 

 The upper part of the body is not in any instance well preserved ; but the neural 

 spines are seen to have an elevation of 0'02 m., and the fragmentary remains of 



