Jordan and Evermann. Fishes of North America. 2105 



Family CLXXXIII. LIPARIDID^E. 

 (THE SEA SNAILS.) 



Body more or less elongate, tadpole-shaped, subcylindrical anteriorly, 

 compressed behind, the head depressed; both head and body covered with 

 smooth, thin skin, which is very lax. Head broad, obtuse, the snout short, 

 wide, and blunt; third suborbital bone styliform behind, forming a bony 

 stay articulating with the preopercle, as in Cottidcv, mouth moderate, 

 anterior, terminal, the jaws equal, or the lower included; jaws with 

 bands of small teeth, which are simple or more or less tricuspid, usually 

 close set, forming a pavement; no teeth on vomer or palatines; premaxil- 

 laries protractile, little movable ; opercular bones unarmed ; interopercle 

 slender, ray-like, overlying the branchiostegals ; gill openings small, the 

 membranes joined to the broad isthmus and to the humeral arch below. 

 Branchiostegals 6. Gills 3^, no slit behind the last; pseudobranchiae 

 small or wanting; dorsal fin rather long, the spines feeble and flexible, 

 low, similar to the soft rays; anal long, similar to the soft dorsal; ventral 

 iins 1, 5, the two completely united and forming the bony center of an oval 

 sucking disk, or else sometimes entirely wanting ; pectoral fin very broad, 

 the base procurrent, extending forward under the throat, the outline 

 usually emargiiiate, some of the lower rays being produced; tail diphy- 

 cercal; caudal fin short, convex; vertebrae numerous, 35 to 50; pyloric 

 cteca numerous; no air bladder; stomach siphoual, U-shaped, intestine 

 elongate. Genera 9; species about 40. Small, sluggish fishers, nearly all 

 of the Arctic seas, a few belonging to the Antarctic ; found adhering to 

 rocks at various depths. The group is evidently closely allied to the- 

 Cottidw, and its origin must be sought in the ancestors of such types as 

 Psychrohitcs and Cottunculm, the Cyclopteridw representing a coordinate 

 phase of degradation. 



The following additional characters are given by Mr. Garman : 



Skeleton with a somewhat larger proportion of osseous matter than that of the Cyclopter- 

 idce. As in that family, the skull is full on the back, as if truncate, and has no passage 

 for muscles extending forward between the mastoid and the occipitals. Third suborbital 

 very long, slender, and spine-like, posteriorly reaching toward the posterior margin of 

 the preoperculum. Upper limb of preoperculum expanded. Operculum much reduced, 

 its shape with some resemblance to that of a boot, the sole directed downward and the toe 

 backward. Suboperculum slender, like an inverted V with the limbs curved outward, 

 the anterior extending forward along the preoperculum, and the posterior reaching back 

 under the lower border of the operculum. Interoperculum long, styliform, reaching from 

 suboperculum to articular, frequently mistaken for one of the branchiostegalrays. Rea- 

 sons for separating this family from the Cyclopteridce and placing it farther from the 

 Cottidce exist in the continuous dorsal, the connection of dorsal and anal with the caudal, 

 the more complete transformation of the ventral rays, the more slender and spine-like 

 suborbital process, the expanded upper limb of the preoperculum, the styliform inter- 

 operculum, the shorter olfactory nerves, and the more elongate brain. (Garman.) 

 Discoboli liparidina, GUNTHEB, Cat., in, 158 to 165, 1861. 



LlPARIDIN^E : 



a. Ventral disk present, large or small. 



b. Ventral disk normal, composed of 13 lobes, a median one in front, and one cor- 

 responding to each of the fin rays, each lobe with a deciduous horny cover- 

 ing or papilla. Teeth close set in pavement-like bands, tricuspid in the 

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