364 
ACTINOPTERYGir. 
extending over the head. No differentiated lateral line, but the 
slime-canal-system piercing scales all over the flank. A division of 
the stomach extremely muscular. 
A figure of the skeleton of the existing Miigil is published by 
Agassiz, Poiss. Poss. vol. v. pi. P. 
Mugil princeps, Agassiz. 
1818. Mugil cepholus, H. D. de Blainville, Nouv. Diet. d’Hist. Nat. 
vol. xxvii. p. 370 (eirore). 
1843-44. Mugil princeps, L. Agassiz, Poiss, Poss. vol, v. pt, i. p. 121, 
pi. xiviii, figs. 1, 2. 
Type. Imperfect fish ; School of Mines, Paris. 
A small species, attaining a length of about 0’25. Length of 
hea.d with opercular apparatus slightly exceeding maximum depth of 
trunk and occupying nearly one quarter of the total length of the 
fish. Poremost spine of anterior dorsal fin much, stouter and larger 
than the others ; distance between the origin of this and the posterior 
dorsal fin greater than that between it and the occiput, about equal 
to the distance between the origin of the posterior dorsal and the 
caudal; posterior dorsal relatively small, with one spine and seven 
articulated raysanal much larger than the posterior dorsal, about 
half in advance of the latter, exhibiting apparently three spines and 
eight or nine articulated rays. 
Form. ^ Loe. Lower Oligocene : Aix-en-Provence, Prance. 
8065. Remains of large specimen in friable marl, wanting caudal 
fin. Mantell Coll. 
8036. Head and abdominal region of still larger specimen, better 
preserved. The operculum is shown to be about as broad 
as deep. The pelvic fins exhibit indications of five 
articulated rays and an anterior spine. The scales are 
especially well-preserved, displaying the square form and 
radiating grooves of their oveHapped portion, and often 
the round median perforation for the slime-canal. 
Mantell Coll. 
8067. Small fish, resembling the two smaller specimens figured by 
Agassiz. Mantell Coll. 
40520, 43440. T wo similar specimens. Purchased, 1867, 
and Presented hy Kenneth Murchison, Esq., 1872. 
