202 
ACTINOPTERYGII. 
P. 4381. Nearly complete fish 0*13 in length, wanting the paired 
fins; Pnrbeck Beds, Swanage. Enniskillen Coll. 
Mesodon simus, Sauvage. 
1893. Mesodon simus, H. E. Sauvage, Bull. Soc. Hist. Nat. Autun, 
yoI. vi. p. 441. 
Type. Nearly complete fish. 
A species described by Sauvage as closely resembling M. daviesi , 
but differing in the somewhat more elongated form of its trunk. 
Form. Sf Log. Lower Kimmeridgian: Orbagnoux, Ain, Erance. 
Not represented in the Collection. 
Mesodon comosus, Thiolliere. 
1858. Mesodon comosus, V. Thiolliere, Bull. Soc. Geol. France, [2] 
vol. xy. p. 783 (name only). 
1873. Mesodon comosus, P. Gervais, in V. Thiolliere, Poiss. Foss. 
Bugey, pt. ii. p. 13, pi. ii. fig. 1. 
Type. Fish, wanting head; Lyons Museum. 
A species as large as M. daviesi , distinguished from all known 
forms by its remarkably short and deep dorsal and anal fins. 
Dorsal fin with about 27, anal fin with not less than 22 rays. 
Squamation covering much more than half of the trunk. 
Form. Sf Log. Lower Kimmeridgian (Lithographic Stone) : Cirin, 
Ain, France. 
Not represented in the Collection. 
Mesodon liassicus (Egerton). 
1854. Pycnodus liassicus, Sir P. Egerton, Ann. Mag. Nat. Hist. [2] 
vol. xiii. p. 436. 
1855. Pycnodus liassicus, Sir P. Egerton, Figs. & Descript. Brit. 
Organic Remains (Mem. Geol. Surv.), dec. viii. no. 10, pi. x. 
1856. Mesodon liassicus, J. J. Heckel, Denkschr. k. Akad. Wiss., 
math.-naturw. Cl. vol. xi. p. 202. 
Type. Imperfect fish; British Museum. 
An imperfectly known small species, about 0'13 in length. 
Maximum depth of the trunk less than the length of the head and 
trunk without caudal fin. Teeth smooth. Ornamentation of scales 
and external bones consisting of closely arranged, large, flattened 
tubercles. 
Form. 6f Log. Lower Lias: Leicestershire, Somersetshire, and 
Gloucestershire, 
19864. Type specimen ; Barrow-on-Soar, Leicestershire. 
Purchased , 1846. 
