Of Acanthopterygians the following are known:—Sebastes; Chirus, Agrammus; Podabrus, Blepsias, Cottus, Centridermichthys, Hemilepidotus, Agonus; Trichodon; Callionymus; Liparis; Dictyosoma, Stichæus, Centronotus.
Labroids are absent; they are clearly a type unable to endure great cold; of the Embiotocoids which represent them in the Pacific, one species only (a species of Ditrema) is known from this district.
The Gadoids are, so far as we know at present, sparsely represented, viz. by isolated species of Gadus, Motella, and Lotella, the latter being an inhabitant of moderate depths rather than of the surface. Hippoglossus, Pleuronectes, and Parophrys, seem to occur everywhere at suitable localities.
The Physostomes are nearly the same as in the British district, viz. a Smelt (Hypomesus), probably also the Arctic Mallotus, an Anchovy, several species of Clupea, and the Conger-eel. A very singular Salmonoid fish, Salanx, which is limited to the north-western Pacific, occurs in great abundance.
Also, the Lophobranchs correspond in their development to those of the British district, Nerophis being replaced by Urocampus.
Neither Myxinoids nor Branchiostoma have as yet been found.
2. The Japanese district is, like the Mediterranean, distinguished by a great variety of forms; some of them are peculiar to it (marked J. in the following list); others occur in the Mediterranean, though also in other districts (M.) The resemblance to the Mediterranean is even greater than would appear from the following list of genera, inasmuch as a considerable number of species are identical in both districts. Three of the Berycoid genera have hitherto been found in the Japanese and Mediterranean districts only, and nowhere else. Another very singular fact is that some of the most characteristic genera, like Mullus, Zeus, Callionymus, Centriscus, inhabit the Mediterranean and Japanese districts, but have never reached the opposite American coasts, either in the Atlantic or Pacific; although, at least in the latter, the oceanic currents would rather favour than obstruct their dispersal in the direction towards America. Bold as the hypothesis may appear, we can only account for the singular distribution of these shore fishes by assuming that the Mediterranean and Japanese seas were in direct and open communication with each other within the period of the existence of the present Teleosteous Fauna.
Gadoids have disappeared, or are represented by forms inhabiting moderate depths. Neither Myxine nor Branchiostoma are known to have as yet been found.
List of Japanese Shore Fishes.
Chimæra (M.)