8 
and tliG anal ; anal fin also short and triangular ; upper lohe of tail much 
lirodnced, the caudal fin heing powerful and deeply forked ; small fulcra 
present upon all the fins. Scales very small [superficially striated, H(jertoii\ ; 
large oat-shaped scales, finely striated, upon the sides of the caudal lohe, and 
prominent fnlcral scales upon its upper border, 
Ohs . — This genus was founded l>y Sir Phili]) Egerton upon the middle 
portion of a fish destitute of fins, from Chapel Hill, near Camphclltown, and 
upon the anterior half of another similar fish from Cockatoo Island, only known 
to him hy a photograph transmitted hy the Ilev. AV. B. Clarke. The characters, 
so far as discernible, were considered to denote a close relationship with 
Acrolepis, thus placing the genus in the family of the Balaeoniscidm; and this 
interpretation has subsequently been generally adopted. The specimens in 
the present collection now render it possible to complete the diagnosis as given 
above ; and, though exhibiting hut few anatomical details, they make known 
the general features of at least tAvo well-marked species. 
A careful study of the ugav fossils suggests the comparison of Mijrio- 
lepis Avith Thrissonotus* from the LoAver Lias of Lyme Begis, Dorsetshire, 
the only essential difference in the single knoAvn specimen of the English 
Liassic genus heing the considerable elongation of the anal fin. 
Mykioleims Clakkei, Eyerton. 
PI. II, Pigs. 3, 4 ; PI. Ill, Figs. 1. 
Mi/riolciyis Glarhei, Pgerton, Quart. Joura. Geol. Soc., 18(!1, vol. xx., p. 8, PI. I, (ig. 1, 
Ohs . — Tlie type species is represented hy several fossils, pertaining 
both to old and young individuals, and the information afforded hy the 
folloAving fhu specimens is of especial value : — 
{a) A large complete fish, probably about 0‘435 in length, and 
shoAvn of half the natural size in PI. II, Eig. 3. (The specimen 
has been broken across, immediately lichind the pelAuc fins, and 
the Avrong halA'es of the counterpart unfortunately united, 
leaAu'ng a gap in the middle that did not exist originally. The 
figure is thus in part restored, Avitli the help of Egerton’s 
draAving already quoted.) 
* Sir riiilip de M. Grc_v Egerton, “Figures and Descriptions of British Organic Keniaius,” Mem. Gcol. 
Surv. Gt. Brit., 1858, Dec. ix, No. 2, I’l. ii. 
