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Show 6 6 2 SIR C. ELIOT ON NUDIBRANCHS [June 19, As Bergh observes, it is somewhat doubtful if this is merely a variety of Doridopsis tuberculosa or a new species. I have a specimen captured by Mr. Gardiner at Rotuma, which is of a uniform brownish yellow without a trace of spots, but in other respects apparently a typical Doridopsis tuberculosa. D o r id o p s is d e n is o n i (Angas). (Dorisdeniso7iiAng&s, " Descrip, d'especesnouv. deMoll. nud.," J. de Conchyl. 3 s£r. iv. 1, 1864, p. 45. Doridopsis denisoni Bergh in Semper's Reisen, xv. p. 694, ff. Doridopsis yemmacea A. & H. 1. c. p. 126, and Hancock, "Anatomy of Doridopsis.") According to Bergh, Angas's name has a few months' priority over Alder and Hancock's D. yemmacea. The three specimens are not very well preserved, but appear to agree with Alder and Hancock's two descriptions cited above both externally and internally. The mouth-gland is large and consists of many finely divided lobes. The liver is flattish, much lobed, and deeply cleft behind. No hooks or spines could be found in the male genitalia, although they are no doubt really present. The vas deferens is extremely long and elaborately coiled. D o r id o p s is a t r o m a c u l a t a A. & H. (A. & H. 1. c. p. 129; and Hancock, " Anatomy of Doridopsis," p. 193.) One specimen, rather well preserved. It is as described by Alder and Hancock, though the structure of the mouth-parts is obscured owing to this portion of the body having been opened. Superficially the back appears to be white with black tubercles, but on a closer examination it is seen that the whole surface is studded with groups of tubercles, or with compound tubercles, which are in some places white and in others black. Even in the black regions the tips of the tubercles are whitish. The structure of the branchia is remarkable. The plumes arise from a large common ring which, as preserved, projects considerably above the edge of the branchial pocket. Three of them are tripinnate, elongate, but not very ample ; in position they are right, left, and posterior. The anterior part of the ring bears a number of small inconspicuous bipinnate plumes, and there are a few more between the left and the posterior plumes. The right and posterior plumes are close together, the arrangement not being quite symmetrical. The large anal papilla lies somewhat to the left of the centre of the ring. Doridopsis punctata has also only three branchiae, but the arrangement is different, the plumes being tripinnate and fairly ample, without intermediate smaller tufts. Hancock's statement that " the proboscis is quite slender and tapers imperceptibly into the crop " raises a doubt if the animal may not really be a Doriopsilla (see below). |