Fig. 455.—Bryostemma tarsodes Jordan & Snyder. Unalaska.
Fig. 456.—Exerpes asper Jenkins & Evermann. Guaymas, Mexico. Family Blenniidæ.
The Northern Blennies: Xiphidiinæ, Stichæiniæ, etc.—The blennies of the north temperate and arctic zones have the dorsal fin more elongate, the dorsal fin usually but not always composed entirely of spines. The scales are small and the ventral fins generally reduced in size. These are divided by Dr. Gill into several distinct families, but the groups recognized by him are subject to intergradations.
Fig. 457.—Gunnel, Pholis gunnellus (L.). Gloucester, Mass.
Fig. 458.—Xiphistes chirus Jordan & Gilbert. Amchitka I., Alaska.
Chirolophis (ascanii) of north Europe is remarkable for the tufted filaments on the head. These are still more developed in Bryostemma of the North Pacific, Bryostemma polyactocephalum and several other species being common from Puget Sound to Japan. Apodichthys (flavidus) of California is remarkable for a large quill-shaped anal spine and for the great variation in color, the hue being yellow, grass-green, or crimson, according to the color of the algæ about it. There is no evidence, however, that the individual fish can change its color, and these color forms seem to be distinct races within the species. Xererpes fucorum of California lies quiescent in the seaweed (Fucus) after the tide recedes, its form, color, and substance seeming to correspond exactly with those of the stems of algæ. Pholis gunnellus is the common gunnel (gunwale), or butter-fish, of both shores of the North Atlantic, with numerous allies in the North Pacific. Of these, Enedrias nebulosus, the ginpo, or silver-tail, is especially common in Japan. Xiphidion and Xiphistes of the California coast, and Dictyosoma of Japan, among others, are remarkable for the great number of lateral lines, these extending crosswise as well as lengthwise. Cebedichthys violaceus, a large blenny of California, has the posterior half of the dorsal made of soft rays. Opisthocentrus of Siberia and north Japan has the dorsal spines flexible, only the posterior ones being short and stiff. The snake-blennies (Lumpenus), numerous in the far North, are extremely slender, with well-developed pectorals and ventrals. Lumpenus lampetræformis is found on both shores of the Atlantic. In Stichæus a lateral line is present. There is none in Lumpenus, and in Ernogrammus and Ozorthe there are three. All these are elongate fishes, of some value as food and especially characteristic of the Northern seas. Fossil blennies are almost unknown. Pterygocephalus paradoxus of the Eocene resembles the living Cristiceps, a genus which differs from Clinus in having the first few dorsal spines detached, inserted on the head. The first spine alone in Pterygocephalus is detached and is very strong. A species called Clinus gracilis is described from the Miocene near Vienna, Blennius fossilis from the Miocene of Croatia, and an uncertain Oncolepis isseli from Monte Bolca. The family is certainly one of the most recent in geologic times. The family of Blenniidæ, as here recognized, includes a very great variety of forms and should perhaps be subdivided into several families, as Dr. Gill has suggested. At present there is, however, no satisfactory basis of division known.
