434 
actinopierygii. 
The so-called Platax (?) colchicus from the Lower Tertiary of the 
Caucasus (Simonovich, Batzevich, and Sorokin, Material. Cool. 
Kavkaza, 1875, p. 102, pis. i.-iii.) docs not belong to this genus, 
and cannot be satisfactorily determined from tho published 
description and figure. 
Genus AMPHISTIUM, Agassiz. 
[Poiss. Foss. vol. v. pt. i. 1844, p. 44.] 
Trunk much deepened, and head short and deep, with rather 
large supraoecipital crest. Eye largo ; cleft of mouth of moderate 
size and directed upwards ; teeth minute or absent. Paired fm* 
small, the pelvic pair inserted in advance of the pectorals ; dorsa 
fin not much elevated, extending along the greater part of the back, 
with .1 or 4 feeble anterior spines ; anal fin almost or quite as mac j 
extended as tho dorsal, with 3 or 4 feeble anterior spines ; caudal 
fin rounded. Scales very small, none enlarged or thickened. 
Amphistium paradoxum, Agassiz. 
1790. Pleuronectes platrssa, G. S. Volta, I Unlit. Veronese, p. dxxix- 
pi. xliv. fig. 1 (err ore), 
1818 . Pleuronectes platessa, H. D. do Blainville, Nouv. Diet. d’Hist, 
Nat. vol. xxvii. p. 357 ( errore ). 
1835. Amphistium paradoxum, L. Agassiz, Neues Jahrb. p. 294 ( nanu 
only). 
1834-44. Amphistium paradoxum, L. Agassiz, Poiss. Foss. vol. v. pi • *• 
p. 44, pi. xiii. 
'I lipe. Nearly complete fish ; Museum of Natural History, 1 ;ir ' s ‘ 
The type species, attaining a length of about 0-2. Length ot 
head with opercular apparatus somewhat exceeding half the 
maximum dopth of the trunk, which is contained twice or slightly 
less in the total length to the base of the caudal fin. Dorsal ant 
anal fins gently rounded and equally olovatod, each with from 21 to 
23 stout, articulated and divided rays. 
Form, cj- Loc. Upper Eocene : Monte Bolca, near Verona ; Mont- 
martre, near Paris. 
P. 1982. Fine largo specimen, wanting extremity of caudal H n ’ 
Monte Bolca. The articulation of the mandible is bencat 1 
the orhit, and the upturned mouth bears traces of rninu 
teeth. Tho operculum is quite smooth. The cau a 
portion of the vertebral column is nearly straight, but 
very short abdominal portion curves sharply upwar 
