The genus Zesticelus contains small soft-bodied sculpins from the depths of the North Pacific. Zesticelus profundorum was taken in 664 fathoms off Bogoslof Island and Zesticelus bathybius off Japan. In this genus the body is very soft and the skeleton feeble, the result of deep-sea life. Another deep-water genus less degraded is Cottunculus, from which by gradual loss of fins the still more degraded Psychrolutes (paradoxus) and Gilbertidia (sigolutes) are perhaps descended. In sculpins of this type the liparids, or sea-snails, may have had their origin. Among the remaining genera Gymnocanthus (tricuspis, etc.) has no vomerine teeth. Leptocottus (armatus) and Clinocottus (analis) abound on the coast of California, and Pseudoblennius (percoides) is found everywhere along the shores of Japan. Vellitor centropomus of Japan is remarkable among sculpins for its compressed body and long snout. Dialarchus snyderi of the California rock-pools is perhaps the smallest species of sculpin, Blepsias (cirrhosus), Nautichthys (oculofasciatus), and Hemitripterus (americanus), the sea-raven, among the most fantastic. In the last-named genus the spinous dorsal is many-rayed, as in Scorpænidæ, a fact which has led to its separation by Dr. Gill as a distinct family. But the dorsal spines are equally numerous in Jordania, which stands at the opposite extreme of the cottoid series.
Fig. 395.—Blepsias cirrhosus Pallas. Straits of Fuca.
Fig. 396.—Sea raven, Hemitripterus americanus (Gmelin). Halifax, Nova Scotia.
Fig. 397.—Oligocottus maculosus Girard. Sitka.
In Ascelichthys (rhodorus), a pretty sculpin of the rock-pools of the Oregon region, the ventral fins are wholly lost. Ereunias grallator, a deep-water sculpin from Japan, without ventrals and with free rays below its pectorals, should perhaps represent a distinct family, Ereuniidæ.
The degeneration of the spinous dorsal in Psychrolutes and Gilbertidia of the North Pacific has been already noticed. These genera seem to lead directly from Cottunculus to Liparis.
Fossil Cottidæ are few. Eocottus veronensis, from the Eocene of Monte Bolca, is completely scaled, with the ventral rays I, 5. It is apparently related to Jordania, but is still more primitive. Lepidocottus (aries and numerous other species, mostly from the Miocene) is covered with scales, but apparently has less than five soft rays in the ventrals. Remains of Oncocottus, Icelus, and Cottus are found in Arctic Pleistocene rocks. The family as a whole is evidently of recent date.