Fig. 406.—Lumpfish, Cyclopterus lumpus (Linnæus). Eastport, Me.
Fig. 407.—Liparid, Crystallias matsushimæ, (Jordan and Snyder). Family Liparididæ. Matsushima Bay, Japan.
The Sea-snails: Liparididæ.—The sea-snails, Liparididæ are closely related to the lumpfishes, but the body is more elongate, tadpole shaped, covered with very lax skin, like the "wrinkled skin on scalded milk." In structure the liparids are still more degenerate than the lumpfishes. Even the characteristic ventral disk is lost in some species (Paraliparis; Amitra) and in numerous others the tail is drawn out into a point (leptocercal), a character almost always a result of degradation. The dorsal spines are wanting or imbedded in the loose skin, and all trace of spines on the head is lost, but the characteristic suborbital stay is well developed. The numerous species are all small, three to twelve inches in length. They live in Arctic waters, often descending to great depths, in which case the body is very soft. One genus, Enantioliparis, is found in the Antarctic. In the principal genus, Liparis, the ventral disk is well developed, and the spinous dorsal obsolete. Liparis liparis is found on both shores of the North Atlantic, and is subject to large variations in color. Liparis agassizi is abundant in Japan and northward, and Liparis pulchellus in California. In the most primitive genus, Neoliparis, a notch in the fin indicates the separation of the spinous dorsal. Neoliparis montagui is common in Europe, replaced in New England by Neoliparis atlanticus. Careproctus, with numerous elongate species, inhabits depths of the North Pacific. In Paraliparis (or Hilgendorfia) ulochir, the ventral disk is gone and the lowest stage of degradation of the Loricate or Scorpæna-Cottus type of fishes is reached. No fossil lump-suckers or liparids are recorded, although remains of Cyclopterus lumpus are found in nodules of glacial clay in Canada.
Fig. 408.—Snailfish, Neoliparis mucosus (Ayres). San Francisco.
The Baikal Cods: Comephoridæ.—The family of Comephoridæ includes Comephorus baikalensis, a large fresh-water fish of Lake Baikal in Siberia, having no near affinities with any other existing fish, but now known to be a mail-cheek fish related to the Cottidæ. The body is elongate, naked, with soft flesh and feeble skeleton. The mouth is large, with small teeth, and the skull has a cavernous structure. There are no ventral fins. The spinous dorsal is short and low, the second dorsal and anal many-rayed, and the pectoral fins are excessively long, almost wing-like; the vertebræ number 8 + 35 = 43, and unlike most fresh-water fishes, the species has no air-bladder. Little is known of the habits of this singular fish. Another genus is recently described under the name of Cottocomephorus.
Suborder Craniomi: the Gurnards, Triglidæ.—A remarkable offshoot from the Pareioplitæ is the suborder of gurnards, known as Craniomi (κράνιον, skull; ὤμος, shoulder). In these fishes the suborbital stay is highly developed, much as in the Agonidæ, bony externally and covering the cheeks. The shoulder-girdle is distorted, the post-temporal being solidly united to the cranium, while the postero-temporal is crowded out of place by the side of the proscapula. In other regards these fishes resemble the other mail-cheek forms, their affinities being perhaps closest with the Agonidæ or certain aberrant Cottidæ as Ereunias.
In the true gurnards or Triglidæ the head is rough and bony, the body covered with rough scales and below the pectoral fin are three free rays used as feelers by the fish as it creeps along the bottom. These free rays are used in turning over stones, exploring shells and otherwise searching for food. The numerous species are found in the warm seas. In Europe, the genus Trigla, without palatine teeth and with the lateral line armed, is represented by numerous well-known species. Trigla cuculus is a common form of the Mediterranean. Chelidonichthys, similar to Trigla but larger and less fully armed, is found in Asia as well as in Europe. Several species occur in the Mediterranean. Chelidonichthys kumu is a common species in Japan, a large fish with pectorals of a very brilliant variegated blue, like the wings of certain butterflies.