EASTMAN: DESCRIPTIONS OF BOLCA FISHES. 



33 



pal characters are combined in the accompanying text-figure, so far as they are 

 observable. There is little room for doubt that these interesting and rare 

 pediculates are identical with the species described by Baron de Ziguo under 

 the name of Histiocephalus bassani, although the type-specimen is so imper- 

 fectly preserved that his description is at variance in some points with the 

 one given above, and the affinities of the type have remained more or less 

 obscure. The latter, indeed, was referred to the Scorpaenidae by Dr. A. S. 

 Woodward in his Catalogue of Fossil Fishes in the British Museum. The 

 characteristic pectoral members are not shown in de Zigno's illustration of 

 this form, and the head is much disfigured; as for a supposed membrane sui> 

 ported by the cephalic spines (to which the name Histiocephalus alludes), no 

 indication is afli"orded by the new material that such a structure existed. An 

 interesting fact to be noted is the close correspondence existing between the 

 fin-formulae of the fossil and recent species. In the common Angler, Lopliius 



Fig. C. Ilistiuiiotuii/(Oiusliiissani(de7.)gno). X J A comjiosite ilrawing based 

 upon tliree individuals belonging to tlie Miis. Conip. Zool. 



piscatorius, for instance, as well as in the form under discussion, the first and 

 second dorsal together comprise 13 rays, and the number of rays belonging to 

 the caudal, anal, and ventral fins is identical in both species. 



It is to be regretted that the cranial osteology is not more clearly displaye<l, 

 as it would be interesting to compare the various degrees of modification 

 exhibited by the Eocene and modern pediculates. The recent genus Corynolo- 

 phus exhibits a similar tliiekening of the dentary and other bones of the lower 

 jaw, and another resembluice is seen in the construction of the premaxillaries, 

 which are probably movable, but further than this we cannot go. Attention 

 should be called, however, to the remarkable fact of a type of fish-life appear- 

 ing suddenly in the Eocene, already highly modified, without any known 

 predecessors nor any that can be plausibly conjectured, but which persists after 

 its first introduction essentially unchanged until modern times. 



VOL. XLVI. NO. 1 3 



