398 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
LL. Spinons dorsal well developed, depressilde in a groove 
— Scales minute or wanting ; premaxillaries non-pro-. 
tractile Scombuid.k, 74. 
Scales of moderate size; premaxillaries protrac- 
tile N 0 MKID. 1 ;, 70 (b). 
LLL. Spinous dorsal little developed, or not distingnisliahle 
from the soft parts; no tiulets. 
M. ffisophagns without tooth-like process. ConYPii-EXiD.E, 79. 
MM. GUsophagns with tooth-like process. .. Stromateid.e, 77. 
KK. Vertebne 25 (24-26); two free anal siiines (sometimes obso- 
lete). 
N. Scales minute or obsolete, cycloid; tail v idely forked. 
CARANGIDiE, 75. 
NN. Scales small, weakly ctenoid; tail little forked. 
POJIATOMID.E, 76. 
II. Scales well developed, mostly ctenoid;* caudal peduncle not 
especially slender. 
O. Pectoral with the lower rays detached and liliform ; 
two short, separated dorsal tins; 
head with mneiferons system well 
developed. 
POLYXEMID.E, 68. 
00. Pectoral fin entire. 
P. Throat with two barbels; dorsals two; scales large. 
MULLID.E, 90. 
PP. Throat without barbels. 
Q. Skull cavernous; anal spines 1 or 2; lateral line 
extending on the caudal fin; head 
scaly; no teeth on vomer. 
SciJiXID.E, 91. 
QQ. Skull not especially cavernous. 
R. Anal fin comparatively short, with less than lilt 
soft rays ; vomer mostly with 
teeth. (Pcrciform fishes.) 
S. Scales caducous; dorsal fins two, the first short; 
mouth very ohlicine. 
Apogonii)^, 89. 
SS. Scales adherent. 
T. Anal si)ines 1 or 2; dorsal fins 2; psendo- 
hrauchite small or obsolete. 
PERCID.E, 8.5. 
TT. Anal spines 3t or more (rarely obsolete). 
U. Psendobranchise small, covered by the 
skin, or obsolete. 
V. Vomerine teeth ; lateral line present. 
Elassomatii).e, 83 {!>}. 
VV. Vomerine teeth none; lateral line obso- 
lete Centrarciiid.e, .'^4. 
UU. Psendohranchim well developed. 
W. Maxillary not slipping under preor- 
bital for its whole length. 
* Small or wanting in some Uranoscopidw, Trichodonliclw, and Icosteida^. 
t Except in some Sjyarida, Priacaiitliida’, Venirarchidw, etc. 
t Obsolete in some Serranidev, more than thi'ce in some Ccntrarchidcc. 
