566 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
Family XCI. — SCI^NID^. 
{The Croalcers.) 
Body compressed, more or less elongate, covered with rather thin, 
ctenoid scales. Lateral line continuons, extending on the caudal flu. 
Head iirominent, covered with scales. Bones of the skull cavernous, 
the muciferous system highly developed, the surface of the skull, when 
the flesh is removed, very uneven. Chin usually with pores, sometimes 
Avith barbels. Mouth small or large, the teeth in one or more series, the 
outer of which are sometimes enlarged; canines often present. INo in- 
cisor nor molar teeth ; no teeth on A omer, palatines, pterygoids, nor 
tongue. Maxillary without supplemental bone, slipping under the free 
edge of the preorbital. Premaxillaries protractile, but not very freely 
movable. Nostrils double. Pseudobranchim usually large, present in 
all our genera. Gills 4, a slit behind the fourth. Gill-rakers present. 
Branchiostegals V. Gill-membranes separate, free from the isthmus. 
Lower pharyngeals separate or united. Preopercle serrate or not. 
Opercle usually ending in two flat points. Dorsal fin deeply notched, 
or divided into two fins, the soft dorsal being the longer, the spines 
depressible into a more or less perfect groove. Anal fin with 1 or 
2 spines. Ventral fins thoracic, I, 5. Pectoral fins normal. Caudal 
fin usually not forked. Ear-bones very large. Pyloric coeca usually 
rather few. Air-bladder usually large and complicated (Avant iug in ]\[en- 
ticirrus). Most of the species make a peculiar noise, called Amriously 
croaking, grunting, drumming, and snoring. This sound is supposed 
to be caused by forcing the air from the air-bladder into one of the lat- 
eral horns. Carnivorous. An iihpo"tant family of about 25 genera and 
125 species, found in all warm seas, one species being confined to fresh 
Avaters. Many of them reach a large size, and nearly all are valued for 
food. 
{Sciosnidce Gunther, ii, 265-318.) 
* Dorsals contiguous, the second dorsal much larger than the anal. 
t VertehrjB about 10 -|-14. (Sciwnince.) 
t Lower jaw included. 
§ Lower pharyngeals fully united, with paved teeth ; second anal spine very large. 
a. Lower jaw without barbels. (Fresh-water si>ecies).HAPLOiDOXOTUS, 204. 
aa. Lower jaw with several small barbels. (Marine species). P ogonias, 295. 
§§ Lower pharyngeal bones distinct. 
6. Lower jaw without barbels ; anal spines 2. 
c. Teeth well developed, persistent in both jaws ScIjENA, 296. 
