. Fig. 9. S. corniitus. a, Mastigopus i; b, telson. Mandibular palp very small, unsegmented. Maxillipede 3 reaching far beyond anten- nules. Hansen has noted the great length of this appendage in young Mastigopus as compared with the adult, a feature which would, if its later development were not known, place it in Hansen's group H. Legs with small vestiges of exopods. Pleopods long, with small rudiment of endopod on pleopod 5 only. Uropod with bare part slightly longer than setose part (1-09 : i). Stage 2 (Fig. 10) differs very little from stage i. The legs have no vestiges of exopods, and th
. Fig. 9. S. corniitus. a, Mastigopus i; b, telson. Mandibular palp very small, unsegmented. Maxillipede 3 reaching far beyond anten- nules. Hansen has noted the great length of this appendage in young Mastigopus as compared with the adult, a feature which would, if its later development were not known, place it in Hansen's group H. Legs with small vestiges of exopods. Pleopods long, with small rudiment of endopod on pleopod 5 only. Uropod with bare part slightly longer than setose part (1-09 : i). Stage 2 (Fig. 10) differs very little from stage i. The legs have no vestiges of exopods, and the pleural spines are reduced. In this specimen the dorsal spines of abdominal somites 1-3 were lost. Two pairs of "luminous organs" (organs of Pesta) in the thorax were noted in specimens of 8 mm. upwards. At a size of 9 mm. the mandibular palp is of full size, but with relatively few setae. The form of the uropods is also changed to that of the adult. The antennule of the male takes the adult form in the last Mastigopus of 12 mm.
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Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
