404 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
dorsal* and anal fins covered with small scales; pectoral fins mostly 
naked, inserted high. Coloration bluish above ; tbe sides silvery, without 
conspicuous dark stripes, but with shining streaks along the rows of 
scales; a dusky blotch at the base of the pectoral; tips of caudal and 
soft dorsal blackish. Ilead 4; depth 4. D. IV— I, 8; A. HI, 9; scales 
38-12; vert. 11 + 13. Cape Cod to South America, and Lower Califor- 
nia; abundant; on our Atlantic coast, usually reaching a smaller size 
than 2[ugil alhula. 
(Agassiz 8pix. Pise. Brazil, 234; Mufil ciirema and Mujil lietrosus Cuv. & Val. xi, 
87, d‘.»; Giiutlier, iii, 431: Mujil Uneaias Storer, Hist. Fish. Mass.) 
Family LXVI.— ATIIFRIXID.E. 
{The Silversides.) 
Body rather elongate, somewhat compressed, covered with cycloid 
scales of moderate or small size. No lateral line; some scales often 
with rudimentary mucous tubes. Cleft of the mouth moderate. Teeth 
small, on jaws and sometimes on vomer and palatines, rarely wanting. 
Premaxillaries protractile or not. Opercular bones without spines or 
serrature. Gill-openings wide, the gill-membranes not connected, free 
from the isthmus. Gills 4, a slit behind the fourth. Pseudobranchim 
present. Gill-rakers usually long and slender. Branchiostegals 5 or 0. 
Dorsal fins 2, well separated, the first of 3-8 feeble, flexible spines, the 
second of soft rays. Anal with a weak spine, similar to the solt dorsal, 
but usually larger. Ventral fins small, abdominal, not far bacli, of 1 
small spine and 5 soft rays. Pectorals moderate, inserted high. Air- 
bladder present. No i)yloric coeca. Caudal and abdominal 4’ertebrm very 
numerous. Carnivorous fishes, mostly of small size, living in great 
schools near the shore in temperate and tropical seas ; a few species in 
fresh water ; nearly all the species have a silvery band along the side. 
Genera about 8 ; species 50. 
CAtherinidw \}t. Giiiithcr, iii, 391-407.) 
a. Premaxillaries freely protractile (their skin not continnons with that of the fore- 
head). 
h. Premaxillary narrow, its edge nearly .straight ; teeth on vomer. .ATiinniNA, 193. 
hi). Premaxillary hroad posteriorly, its edge curved ; no teeth on vomer. 
c. Teeth none LEUUESXirES, 197. 
* Dorsal .and anal partly naked, pectoral wholly so in specimens from North Caro- 
lina; dorsal and anal densely scaly, x^ectoral mostly scaly in specimens from Acapulco, 
Mex., otherwise similar. 
