ACANTHOPTERI. 
397 
Order T.-AC ANT II OPT KRI . 
[The Spiny-rayed Fishes.) 
Crauiam normal, symmetrical ; the maxillary bone distinct from the 
premaxillary, wbicli forms the border of the mouth. Bones of the 
mandible distinct. Gills normal, laminated, rarely reticulated. Gill- 
openings in advance of the pectorals. Opercular apparatus complete. 
Basal bones of jiectorals not enlarged. Pharyngeals well developed, 
the third superior pharyngeal usually largest. Lower pharyngeals 
separate or united. Ventral fii.s variously placed, often wanting, nor- 
mally thoracic and six-rayed, the first ray spiuous. Anterior rays of 
dorsal and anal normally developed as spines, but often soft and artic- 
ulate. Air-bladder, if present, without pneumatic duct. The most ex- 
tensive of the orders of fishes, comprising a great variety^ of forms. 
(azavA/, spiuej -zspo'^^ tin.) 
(AeantJioptcri/gii, PharyngognatM, and Anacanthini Giiiitber, i, ii, iii, iv, exclusive of 
various families. Orders Ftreesoas, Fercomorphi, aud Pharyngognallii Cope, Trans. 
Amer. Phil. !Soc. 1870, 456.) 
ANALYSIS OF FAMILIKS OF ACANTHOPTERI. 
A. Ventral fins abdominal; dorsals two, veil separated. {Percesoces.) 
B. Dentition strong; vertebrm i’4 SPiiYRASNiDji:, 67. 
BB. Dentition feeble; vertebne more than 24 ; carnivorous ATiiERiNiDiE, 66. 
BBB. Dentition feeble ; vertebrfB24; limnophagous Mugilid.e, 65. 
AA. Ventral tins, if present, thoracic or jugular. 
C. Ventral region without sucxiug-disk. 
D. Suborbital without bony stay. 
E. Ventral tins present, the rays in normal number,* I, 5. 
F. Lower pharyngeal bones separate (except in certain Sciainidat) j gills 4, 
a slit behind the last. 
G. Gill-membranes free from the isthmus. 
H. Spinous dorsal transformed into a lamellated sucking-disk, situated 
on the top of the head. 
Eciieneididaj, 70. 
HH. Spinous dorsal not transformed into a sucking-disk. 
I. Scales small or obsolete, mostly cycloid ; spinous dorsal comjiar- 
atively little developed; caudal 
peduncle slender,! the fin widely 
forked.! [Scomhrifonn fishes.) 
K. Vertebrfe more than 24 or 25; no free anal spim-s. 
L. Spinous dorsal represented by free spines; caudal not forked; 
body elongate, fusiform. 
ELACATID.E, 71. 
* Except in certain Stromatcidoe, Acanthuridee, and Icosteidce. 
t Except in Pomatomidee, Elacatidw, aud some Stromateidee, 
