. organs are not very clearly defined it is unwise to state a precise number until more specimens have been carefully examined. On the other hand, however, some of the organs, particularly those on the ocular peduncles, the transverse streak behind the bases of the last thoracic limbs, and those on the inferior margin of the cara- pace, stand out prominently as white streaks and dots against the now dull yellow of the integument. The ocular peduncle photophores (Fig. 19, ) appear as an irregular, somewhat raised white bar, placed on the inner ventral face of the peduncle, and
. organs are not very clearly defined it is unwise to state a precise number until more specimens have been carefully examined. On the other hand, however, some of the organs, particularly those on the ocular peduncles, the transverse streak behind the bases of the last thoracic limbs, and those on the inferior margin of the cara- pace, stand out prominently as white streaks and dots against the now dull yellow of the integument. The ocular peduncle photophores (Fig. 19, ) appear as an irregular, somewhat raised white bar, placed on the inner ventral face of the peduncle, and a pear-shaped similar mass borne on a small ventro- lateral tubercle. Any light produced by these photophores would be shed mainly downwards from the inner side of the peduncle. The transverse streak at the bases of the last pair of thoracic limbs (Plate XXVI, fig. 2, ) is also raised from the surrounding integument, and extends laterally, curving upwards and somewhat forwards on the ventral side of the body. The right and left streaks almost meet in the middle line. They thus occupy precisely the same position as those in the species of Hoplophoriis (p. 337). The branchiostegal photophores (Plate XXVI, fig. 2,) consist, in this specimen at any rate, of a long posterior streak, with fourteen short bars of varying length extending from its anterior end to the anterior end of the lower margin of the carapace, extending in fact to the base of the prominent branchiostegal spine. Although only fourteen streaks are visible superficially, a cleared and mounted portion of the branchio- stegite shows that between them occur numerous very small patches of similar tissue, so that the inferior branchiostegal organs may almost be regarded as constituting a potentially continuous band of photogenic tissue, strongly developed in localized areas. The nature of the deposits of white opaque pigment in the photophores of S. affinis will be considered in detail in the discussion a
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Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
