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Show 1896.] OF THE GENUS SERGESTES. 969 Ortmann's, and Faxon's specimens of S. edwardsl, Kr., must be re-examined, as tbe species is collective; thus some of the localities given in the literature of the subject are untrustworthy and several others are, in m y opinion, not quite certain. But the statements given above as results of m y own studies of the animals prove with absolute certainty that at least a series of the species have a very wide distribution : the Atlantic northward to lat. 23o-30° N. and mostly to lat. 42° N., the Indian Ocean, and at least tbe most western part of the Pacific. From the other parts of the Pacific I have seen no material. Bate writes on p. 352: " The species of this genus [Sergestes'] are chiefly oceanic"; and this is, I think, generally admitted. But partly according to the foregoing investigation this statement must be rather altered, for we must distinguish between tbe larvae and the really mature forms. Almost all known larvae have been taken at the surface. Yet it must be remarked that at least in short distance from the shore some Mastlgopus-species generally are met with in considerable depths. This is proved by Prof. Chun, who in 1889 (p. 538) writes on his " S*longlrostrls, Bate": "Er war der haufigste aller Sergestiden [at the Canary Islands] und fand sich regelmassig in dem Inhalt der Tiefennetze Sel-tener erschien er an der Oberflache." Later on he captured different larger Mastlgopus-stages of S. mediterraneus, m., and S. arcticus, Kr., with intermediate-net (" Schliessnetz"), near Lesina and Ragusa at 80, 100, 400, 500, and 500-600 metres, but all the Mastigopus-stages of S. arctlcus, Kr., are not uncommon near the surface in the northern area of the Atlantic. While all the larvae, according to our present knowledge, are essentiallv oceanic near the surface, the adult forms give another result. I have accepted at most 14 earlier described mature forms as valid speries, and of these 8 species-S. Inous, Fax., S. robustus, Smith, S. japonlcus, Bate ( = S. mollis, Smith), S. bisulcatus, Wood- Mason, S. prehensills, Bate, S. krogeri, Bate, S. rubroguttatus, Wood-Mason, and S. hamifer, And. & Ale.-have only been captured with trawl or dredge between 345 and 2574 fathoms. The other 6 species must be treated separately. S. arctlcus, Kr., is typically (see Metzger, Chun, and especially the long lists given by Smith) an inhabitant of the deep sea, and only some younger specimens with black eyes have been secured at the surface, and one single really mature specimen (the type of Kroyer) in all probability near the shore. Of S. henseni (Ortm.) 2 smaller specimens (not 3, as written by Ortmann), the largest specimen about 24 m m . in length, were captured with the vertical net between 400 and 0 m., while a much larger specimen (35 m m. long) was taken with the trawl from 4000 m. The depth of S. halla, Fax., is not recorded, as the specimens were taken with a submarine tow-net; and if S. armatus, Kr., is the Mastigopus to it, it is certainly no surface species, as S. armatus is not very rare in the northern part of the Atlantic, where no adult form which can belong to it has been secured. S. atlanticus, M.-Edw., is very |
