ACANTHOPTERL 397 



Ordee T.-ACANTIIOrTERI. 



[The Spiny-rayed Fishes.) 



Cranium normal, symmetrical ; the maxillary bone distinct from the 

 premaxillary, wliicli 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 pectorals 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 spinous. 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. 

 {uxayOa, spine; -re/xr^, liu.) 



{Acanthopicrij<jU, I'liaryn(jO(jnatM, and Anacanthini Giiutber, i, ii, iii, iv, exclusive of 

 various families. Orders I'crcesoas, Fercomorphi, and Pliaryngognaihi Cope, Traus. 

 Amer. Phil. Soc. 1870, 456.) 



ANALYSIS OF FAMILIES OF ACANTIIOPTERI. 



A. Ventral fms abdominal; dorsals two, well sexiarated. (Percesoccs.) 



B. Dentition strong; vertebne '24 SpiiyRzENID^, G7. 



BB. Dentition feeble; vertebra? more than 24 ; carnivorous Atiierixid/E, G6. 



BBB. Dentition feeble; vertebrie24; linniopbagous Mugilidje, 65. 



AA. Ventral tins, if present, thoracic or jugular. 

 C. Ventral region without sucking-disk. 

 D. Suborbital without bony stay. 

 E. Ventral fins present, the rays in normal number,* I, 5. 

 F. Lower pharyngeal bones separate (except in certain Sdwnicke); gills 4, 



a slit behind the last. 

 G. Gill-membranes free from th(^ isthmus. 



H. Spinous dorsal transformed into a lainellated sucking-disk, situated 



on the top of the head. 



EciIENEiniD.E, 70. 

 HH. Spinous dorsal not transformed into a sucking-disk. 

 I. Scales small or oltsolete, mostly cycloid; spinous dorsal compar- 

 atively little devel()i)ed ; caudal 

 peduncle slender, t the hn widely 

 forked. t {Scomhriform lishos.) 

 K. VertebriB more than 24 or 25; no free anal spinis. 



L. Spinous dorsal represented by free spines; caudal not forked; 



body elongate, fusiloriu. 



ELACATIDiE, 71. 



* Excejjt in certain StromatcUla', Acanlhunda', and Tcosfeklw. 

 t Except in Pomaiomidcc, IJIacaiida; and some Utromaividw. 



