MACROSEMIIDJE. 
181 
p. 166), described and figured by the present writer in 
Proc. Geol. Assoc, vol. xi. (1890), p. 293, pi. iii. fig. 9 ; 
Stonesfield Slate, Stonesfield. Enniskillen Coll. 
P. 957. Left dentary with eight teeth, probably of the same species ; 
Stonesfield. Egerton Coll. 
The following species is only imperfectly defined and is not 
represented in the Collection :— 
Macrosemius lielence , V. Thiolliere, Ann. Soc. Sci. Phys. & Nat. 
Lyon, [2] vol. iii. (1850), p. 135, and Poiss. Loss. Bugey, 
pt. ii. (1873), p. 14, pi. vi. fig. 2 ; H. E. Sauvage, 
Bull. Soc. Geol. France, [3] vol. xi. (1883), p. 478.— 
Lower Kimmeridgian (Lithographic Stone); Cirin, Ain, 
France. [Imperfect small fish ; Lyons Museum.] 
e /v^z-cA- s - A* E- A/ 4 ? 3, /& x >c A ^ ^ ' 
/*\ t/. /?d T^e^ ay tZQ ^ ' 
Genus PETALOPTERYX, Pictet. . 
[Poiss. Foss. Mt. Liban, 1850, p. 20.] Tyrzrz:—' 
a Jjy, 
Syn^^Apk&ttepyyu, rpF . Bas sani, Ve r l i :m dklrr tr~ge0lrtr~18f9, 
p.462r 
Trunk much elongated, gradually tapering from the occiput 
backwards; head small, snout acute. Teeth much elongated, 
closely arranged; suborbital plates subdivided into numerous small 
tesserae. Fulcra absent, except on the caudal fin; pectoral fins 
much enlarged; dorsal fin consisting of unbranched rays, arising 
shortly behind the occiput and extending continuously to the 
caudal pedicle ; [anal fin apparently absent; caudal fin scarcely if 
at all forked]. Squamation robust and extending over the whole 
trunk, the flank-scales not much (if at all) deepened, but all more 
or less irregular, and the vertical series apparently sometimes 
dichotomous dorsally and ventrally. if /^r 'uz+% £ /?/J3. 
Petalopteryx syriacus, Pictet. 
1850. Petalopteryx syriacus , F. J. Pictet, Poiss. Foss. Mt. Liban, p. 22, 
pi. iii. fig. 1. 
1866. Petalopteryx syriacus , F. J. Pictet & A. Humbert, Nouv. Rech.. 
Poiss. Foss. Mt. Liban, p. 54. 
1882. Petalopteryx syriacus , F. Bassani, Denksckr. k. Akad. Wiss., 
math.-naturw. Cl. vol. xlv. p. 268. 
Type. Nearly complete fish; Geneva Museum. 
The type species, attaining a length of about 0H6. Maximum 
depth of trunk contained nearly four-and-a-half times in its length 
