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Show 338 MR. R. COLLETT ON CERTAIN GOBIOID FISHES. [Mar. 5, few materials at my disposal. In all probability Cryst.nilssonii (as is the case with Latr. pellucidus) maturity at the age of one year, after which it disappears. The spawning-season is probably the same as in the other species, consequently during the summer months; on the whole, however, it appears to have a somewhat longer duration. From the researches I have been able to make among collected specimens, compared with those preserved in the Museum of the University, it appears that the spawning probably begins in some individuals as early as in March or April; perhaps the greater number attain their maturity in the last part of June ; whilst in other specimens the spawning does not take place before the beginning of August, or perhaps later. After the conclusion of the spawning the specimens no doubt perish, their life having thus lasted only one year. Habits.-In its habits this fish probably agrees perfectly with Latr. pellucidus. The extraordinarily compressed body denotes that it swims freely about in rather deep water, and not, like most of the true Gobii, resting itself at the bottom ; in fact this would be almost impossible, on account of the peculiar construction of the ventrals of the male, and, in the case of the female, from its entire want of these fins. Most of the specimens mentioned by other authors have been taken in the dredge at a depth of 30 fathoms. Von Diiben and Koren state that some of their specimens crept into empty tubes of Cheetopterus norvegicus, in which, however, they had only taken refuge whilst the dredging was going on. In the Christiania Fjord I have taken these fishes, together with Latr. pellucidus in nets set out for mackerel, Clupea sprattus, and young of Cl. harengus. The nets bring them to the surface in the same manner as is the case with L. pellucidus. As a rule they lose the capability of again descending, from the swimming-bladder becoming strongly distended when they reach the upper strata of the water. This fish is met with in far less numbers than the last-named species. In the same manner it is taken as food by other fishes; and I have taken it from the stomach of small young examples of Gadus morrhua. Food.-Upon examining a number of stomachs of individuals taken in the month of June, I have found them filled with digested remains of Entomostraca, without, however, being able to recognize any species of them. Probably they were Calanidae, or, perhaps, pelagic Copepoda of the same species as are found in Latr. pellucidus. Distribution.-Besides being found in Norway, Cr. nilssonii has been taken more lately on the coast of Bohuslen (Sweden) ; and perhaps it also occurs on other parts of the coast of Northern Europe. In Norway its habitat extends from the Christiania Fjord along the western coast, nearly to the Trondhjems Fjord, in about 63° N. latitude. The most northern point at which it has been found was at Chris-tiansund, in July 1843, by v. Diiben, and also about the same |
