Davis—On the Fossii Fishes of the Chalk of Mount Lebanon. 533 
posterior margin of the operculum, converging to a more or less pointed apex. 
The pectoral fin is situated on the lateral surface of the body, and is one-fourth 
the height of the body from its abdominal margin. The ventral fin is abdominal, 
situated immediately behind the head; it consists of six rays, dichotomized and 
articulated. 
This species is distinguished from P. discoides principally by the rays of 
the dorsal and ventral fins being much less numerous, and having sixteen caudal 
vertebree instead of eighteen, as in P. discoides. 
Formation and Locality. —Upper Cretaceous: Sahel Alma, Mount Lebanon, 
Ex coll.—Museum at Geneva ; not uncommon. 
Pycnostering russeggerti, HECKEL. 
P. russeggerii. Hecker, J. J., 1843. “ Abbildungen und Beschreibungen der 
Fische Syriens,” p. 236, pl. xxur., fig. la. 
P. russeggerii. Picrer, F. J., 1850. ‘‘ Dese. de quel. poiss. foss. du M. Liban.,” 
ps od. 
P. russeggerii. Picrer et Humperr, 1866. ‘ Nouy. rech. sur les poiss. foss. du 
M. Liban.,” p. 41. 
This species, described by Professor Heckel, was not seen by MM. Pictet and 
Humbert. Neither has the writer had any opportunity to identify the species. 
Formation and Locality.—Soft chalk: Sahel Alma, Mount Lebanon. 
Pycnosterinx dorsalis, Picter. 
(Pl. xxvitt., fig. 2.) 
P. dorsalis. Picrer, J. F., 1850. ‘‘ Dese. de quelques poiss. foss. du M. Liban.,” 
pels, plim, figs3: 
P. dorsalis. Picrer et Humsrrr, 1866. ‘‘ Nouv. rech. sur les poiss. foss. du M. 
Liban.,”’ p. 41. 
This species is distinguished from the two preceding ones by the greater 
elongation of its body and the greater height of the dorsal fin. It is probably 
more closely related with P. russeggerii, Heckel, than with other species of the 
genus. It may be distinguished from the latter by the length of the rays of 
the dorsal fin; by the number of caudal vertebrae, which is at least twenty in 
place of seventeen or eighteen; and by the anal fin, which is supported in 
front by very strong spinous rays. 
Formation and Locality.—Upper Cretaceous: Sahel Alma, Mount Lebanon. 
Ex coll—Museum at Geneva (type); rare. 
TRANS, ROY. DUB. SOC,, N.S. VOL, III. 4D 
