EUGNA.THIDJK. 
351 
Here, Ann. Sci. Phys. & Nat. Lyon, [2] vol. iii. 1850, p. 146, and 
Poiss. Foss. Bugey, pt. ii. 1873, p. 19), from the Lithographic Stone 
(Lower Kimmeridgian) of Ain, France, is also too imperfectly 
described for recognition. / /?*>& 
Genus CALXiOPTERUS, Thiolliere. 
[Bull. Soc. Geol. France, [2] vol. xv. 1858, p. 784, and Poiss. Foss. 
Bugey, pt. ii. 1873, p. 15.] 
A genus apparently differing only from Caturus in the more 
remote situation of the dorsal fin, which is almost completely 
opposed to the anal. The caudal fin also appears to be less deeply 
forked. 
Callopterus agassizi, Thiolliere. 
1846. Lepidotus armcitus, A. Wagner, Gelehrte Anzeig. k. bay. Akad. 
vol. xxii. p. 303 (inadequate definition). 
1858. Callopterus agassizi, V. Thiolliere, Bull. Soc. G6ol. France, [2] 
vol. xv. p. 784. 
1863. Lepidotus armatus , A. Wagner, Abh. k. bay. Akad., math .-phys. 
Cl. vol. ix. p. 620. [Fish ; Palaeontological Museum, Munich.] 
1873. Callopterus agassizi, V. Thiolliere, Poiss. Foss. Bugey, pt. ii. 
p. 15, pi. x. 
1887. Callopterus agassizi, K, A. von Zittel, Handb. Palaeont. vol. iii. 
p. 231, fig. 243. 
Type. Fish ; Lyons Museum. 
The type species, attaining a length of about 0’45. Length of 
head with opercular apparatus somewhat exceeding the maximum 
depth of the trunk and contained about four-and-a-half times in 
the total length of the fish; depth of caudal pedicle about two- 
thirds as great as the maximum depth of the trunk. Mandibular 
teeth especially stout and closely arranged. Pelvic fins twice as 
distant from the pectorals as from the anal; dorsal fin, with 
16 rays, about half in advance of the anal, which has 10 rays. 
Ridge-scales of upper caudal lobe much enlarged, extending half¬ 
way towards the dorsal fin. 
Form . Loc. Lower Kimmeridgian (Lithographic Stone): Ain, 
France. 
Not represented in the Collection. 
A stouter small fish 0-115 in length, from the Lower Kim¬ 
meridgian bituminous limestone of Orbagnoux, Ain, France, has 
also been referred to this genus under the name of Callopterus 
obesus (H. E. Sauvage, Bull. Soc. Hist. Nat. Autun, vol. vi. 1893, 
p. 433, pi. ix. fig. 1). 
