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Show 1878.] MR. R. COLLETT ON CERTAIN GOBIOID FISHES. 329 strings take up the greater part of the belly, without, however, as the case in Cry stal log obius nilssonii, reaching behind the vent along the root of the caudal fin. The number of the eggs is between 1800 and 2000. Habits.-This species, as well as the following differs in its habits in several respects from most of the typical Gobiidee. Above the compressed body the laterally placed eyes indicate that they do not live at the bottom, as is the case with the greater number of Gobies, but swim about freely. Neither do they keep themselves dispersed or in single numbers, but in large and dense shoals, where their perfect transparency, in connexion with their inferior size, enables them to avoid immediate observation. Sometimes I have taken them from the stomachs of other fishes; but by far the greatest number are brought up to the surface by the nets set out for different other fishes, especially for the sprat and the young of the common herring. These fishes are caught in the Christiania Fjord in September and so long as the fjord is free from ice-as a rule, until the beginning of the new year. In the spring and summer, when the nets are drawn for mackerel, they are also to be found, and then with the organs of generation fully developed. These nets are drawn at a depth varying from one to fifteen fathoms. An examination of the stomachs of these fishes shows that they contain chiefly pelagic copepods and the fry of mollusks in their swimming-stages ; these animals principally live in the upper strata of the sea some few fathoms under the surface. The bottom consists, in most of the inner parts of the Christiania Fjord, of clay and mud, which, in the more shallow water, is covered with Zostera. These fishes seem always to keep together in enormously large shoals ; and when the meshes are very fine they are sometimes caught in great masses. The 30th of October 1875 (which was a particularly successful year for their development), I found in a single draught (which, besides, also brought in some young specimens of two or three species of Gadus, several Pleuronectes fiesus, and Cteno-labrus rupestris, some Gobii of common species, and herrings) such large masses of them that I collected between two and three thousand specimens, whilst possibly more than double this number had already escaped through the meshes. In the same year I was not able to notice any diminution of their numbers, and they were always found in the same places; still they are not at all equally numerous every year, and they have been rather scarce both in 1876 and 1877, especially in the latter. In the Mediterranean they must be produced in still greater numbers, as they are caught in very fine nets and sold as food. In several of the fishing-markets in the towns by the Adriatic and in Sicily Prof. G. O. Sars saw vessels filled to the brim with these fishes alone, forming a complete jelly-like mass. Kessler also mentions their use as food in Odessa. Upon the least touch the scales fall off; and after the nets are drawn, scarcely a single specimen will have its scales complete, and the greater number will have lost almost every scale. The proportionally |