532 Davis—On the Fossil Fishes of the Chalk of Mount Lebanon. 
are five branchiostegal rays. Body compressed and elevated. Dorsal and anal 
fins simple and long, commencing near the middle of the body, exclusive of 
the tail, consisting of spinous rays, close to each other, and becoming longer 
by degrees. Ventral fins in a sloping position. Scales closely set, covering the 
occiput, operculum, cheeks, the trunk, and a part of the vertical fins: they are 
small, round, and thick, with smooth concentric circles, of which the central 
point is in the posterior half; border simple, but carrymg sharp denticles. 
Vertebree short, nine to eleven abdominal, seventeen to eighteen caudal. Ribs 
short and slender, the posterior ones supporting long transverse apophyses.” 
Pycnosterina discoides, HEcKEL. 
(Pl. xxvu.., fig. 3.) 
P. discoides. Hecker, 1843. ‘‘Abbildungen und Beschreibungen der Fische 
Syriens,” p. 238 (340), pl. xxu1., fig. 3. 
P. discoides. Picrer, F. J., 1850. “Desc. de quelques poiss. foss. du Mont 
Liban.,” p. 57. 
P. discoides. Picrer and Humpert, 1866. ‘‘ Nouv. recher. sur les Poiss. foss. du 
Mont Liban.,” p. 38, pl. 11, figs. 1, 2. 
A figure of a beautiful example of this species is here given, as it exhibits 
the natural form of the head, which is not so well preserved in the specimen 
figured by MM. Pictet and Humbert. 
Formation and Locality.—Soft chalk: Sahel Alma, Mount Lebanon. 
Ex coll—Museum at Geneva (type); not rare. 
Pycnosterin heckelii, Picrer. 
(Pl. xxvu., fig. 1.) 
P. heckelii. Prcrer, F. J., 1850. ‘‘ Desc. de quel. poiss. foss. du M. Liban.,” 
p- 15, pl. 1, figs. 1, 2. 
P. heckelii. Picrer and Humsrrr, 1866. ‘Nouv. rech. sur les poiss. foss. du 
Mont Liban.,” p. 40, pl. m1., figs. 3, 4. 
The specimens obtained by Prof. Lewis are, in several respects, more perfect 
than those figured by Pictet, and enable me to furnish the following addition to 
the description given. The natural form of the fish is an oval, exclusive of the 
tail. The length is equal to double the height. The head is triangular in 
outline, the mandible forming a broad base, and the facial line and that of. the 
