crossogxathid.t:. 
340 
ossified; cleft of mouth extending as far as or beneath the anterior 
half of the orbit; premaxilla very stout, deepest in front, and its 
slightly convex oral margin bearing a single close series of minute 
conical teeth ; mandible short and deep, the backwardly ascending 
oral margin of the dentary with a similar regular series of slightly 
larger teeth; preoperculum forming a great triangular expansion, 
and suboperculum relatively deep. Vertebral centra much con¬ 
stricted and strengthened on the middle of each side by a sharp 
ridge. Pectoral fins arising near the ventral border ; pelvic fins 
more remote than the anterior part of the dorsal, each comprising 
7 or 8 rays ; dorsal fin imperfectly known, but its anterior portion 
apparently consisting of about 8 spines in which the right and left 
halves are not fused together, its posterior portion of articulated 
and divided rays ; anal fin comparatively small, partly or completely 
behind the dorsal; caudal fin deeply forked, with slender lobes and 
their outermost rays exhibiting numerous closely arranged oblique 
articular lines, which are very finely jagged. Scales large, very 
deeply overlapping, smooth, and not serrated or crenulated on the 
posterior margin. Lateral line conspicuous, a simple tube piercing 
all the scales it traverses, arising low down on the fiank not far 
above the pectoral fin. 
~ This definition is based on the specimens enumerated below. x4n 
examination of the original specimen in the Geneva Museum, on 
which the genus was founded, leaves many essential features in the 
structure of the fish doubtful. The large bone at the margin of the 
upper jaw appears, at first sight, to be a Clupeoid maxilla ; but a 
consideration of the new specimens now described suggests that it 
is a premaxilla most closely resembling that of the Atherinidae. 
The dorsal fin in the type specimen is much more imperfect than 
is indicated in Pictet’s rather diagrammatic figure, only a few frag¬ 
ments remaining. Two pelvic fin-rays in the same specimen seem 
to be displaced backwards ; and the anal fin evidently comprises 
the series of comparatively small and delicate rays observed between 
these and the caudal fin. 
Crossognathus sabaudianus, Pictet. 
1858. Crossognathus sabaudianus, F. J. Pictet, Foss. Terrain Neocom. 
Voirons (Paleont. Suisse), pt. iii. p. 18, pi. ii., pi. iv. figs. 1-6. 
Type. Imperfect fish ; Museum of Natural History, Geneva. 
The type species, attaining a length of about 0'35. Length of 
head with opercular apparatus considerably exceeding the maximum 
depth of the trunk, and contained hbout three and a half times in 
