548 Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 
Gyrodus (Coccodus ?) syriacus, FRAAS. 
G. syriacus. Fraas, O., 1878. ‘Aus dem Orient. II. Theil. Geolog. beobach. am 
Libanon,” p. 92, pl. 1v., figs. 5, 6. 
The figure given by Dr. Fraas appears to indicate that the specimen named by 
him Gyrodus syriacus is closely related to Coceodus armatus, Pictet; and, until 
more perfect examples shall have been examined, it may be advisable to consider 
the question an open one as to whether the one described belongs to the genus 
Gyrodus. Taken simply as a group of teeth, the likeness is sufficiently striking ; 
but, in conjunction with the specimen described by Pictet, there is reason to 
doubt whether it may not be more closely related with it; and, if such be the 
case, then, as already stated with respect to Coccodus, its affinities and relation- 
ship appears to be rather with the Siluroids than the Ganoids. 
Genus. Xenopholis.* Davis. 
Fish, moderate size; head enveloped in strong dermal plates; operculum 
large; spinal column cartilaginous; ribs spinous apophyses, and fin-rays osseous. 
Dorsal and anal fins large, extending from the base of the tail; ventral fins 
midway between the anal and the posterior part of the head. Scales large and 
thick; median lateral line of both upper and under surface is raised in the 
form of a ridge, from which striations branch backwards on each side. 
This fossil fish exhibits several peculiarities which distinguish it from any 
other form discovered in the Lebanon strata. The apparent absence of ossified 
vertebree, combined with the presence of spinous and interspinous bones supporting 
dorsal and anal fins, comprised of simple articulated rays, resembles the Ganoids, 
and recalls the Caturi of the lithographic stone of Sohnhofen; the posterior 
position and extended base of the dorsal and anal fins, however, readily dis- 
tinguish this species from those of Caturus. The large size of the strong plates 
enveloping the head resemble those of the Siluroids; and the scales have more 
than a passing similarity to those of the genus Scopelus; but the unpaired fins 
in this species are again sufficiently characteristic to readily separate it from 
the latter. It is unfortunate that the specimen is not in a better state of 
preservation, so that the character of the head could have been ascertained; it 
would be unsafe to express a very decided opinion as to its relationship until 
more perfect specimens shall have been obtained; but the parts preserved probably 
indicate a closer connection with the Siluroids than with any other group. 
* Eévos, strange; PoArs, a scale. 
