ACTTNOPIERYGII. 
290 
raoiitli; teeth on premaxilla and dentary, none on palate, except 
very rarely on vomer. Opercular apparatus complete, with few 
(4 to 6) . branchiostegal raj-s and no gular plate. Abdominal 
vertebrae.with transverse processes ; ribs stout and long. Pectoral 
arch without precoracoid process. A single dorsal fin, more or 
less remote, without adipose dorsal. Trunk covered with scales, 
which extend more or less over the head. 
The existing Cyprinodonts are small fishes ranging throughout 
the temperate and tropical regions, except Australasia, the majority 
confined to freshwaters, but a few found in brackish water and on 
the sea-coast.^ Only one extinct genus is known with certainty, 
while a second is recognised provisionally. 
Genus PROLBBIAS^ Sauvage. 
[Bull. Soc. Hist. Nat. Toulouse, vol. viii. 1874, p. 187.] 
Trunk regularly fusiform, laterally compressed ; caudal pedicle 
deep. Head very small, with obtuse snout; cleft of mouth 
relatively small; premaxillse not produced forwards, and probably 
not protractile; teeth simply conical, apparently arranged in a 
single series. Transverse processes of abdominal vertebrae very 
short. Pelvic fins present but relatively small; dorsal and anal 
fins small, not much extended, directly opposed in the hinder half 
of the fish ; anal fin never modified ; caudal fin truncated or some¬ 
what forked. Scales large, ornamented with fine parallel striations 
and pectinations. The two sexes apparentl}" similar. 
This genus seems to be most closely related to the existing 
Liicania, Girard, of North America, and Fiindulus^ Lacepede, which 
has a still more extensive range in North America besides being 
abundant in tropical Africa and southern*’Europe. *' - *• 
Prolebias cephalotes (Agassiz). 
1839. Lehias cephalotes, L. Agassiz, Poiss. Foss, vol, v. pt. ii. p. 48, 
pi. xli. figs. 1, 2, 9, 10. 
1874. Prolehias cephalotes, H. E. Saiivage, Bull. Soc. Hist. Nat. 
Toulouse, vol. viii. p. 192. 
1891. Lehias cephalotes, C. Pollini, Sciame Pesci foss. ricopr. Lastra 
Calc, marnoso, with photo. 
Type. Slab with numerous fishes ; olim Murchison Coll. 
The type species, attaining a length of about 0*035. Length of 
head with opercular apparatus about equal to the maximum depth 
^ S. Garman, “ The Cyprinodonts,” Mem. Mus. Comp. Zool. Harvard Coll, 
vol. xix. no. 1 (1895). 
