JAPANESE NÜDIBRANCHS. ]3 



JPlätydoris speciosa Abraham. 



P. S. Abraham, Revision of the Anthobranchiate Nudibr. Mollusca. Proc. Zool. Soc. 1S77, p. 

 250. See also Eliot, Trans. Linn. Soc. xüi, 2, 1910, pp. 425-6, and for PI. formosa 

 id. P. Z. S. 1906, p. 646. 



(Plate I., figs. 3 & 4). 



Three consignments of specimens. (1) Three young speci- 

 mens from Kominato, 40 mm. to 45 mm. long. (2) Five specimens 

 from Misaki ranging from 35 mm to 80 mm. (3) Seven specimens 

 from Moroiso, Misaki, measuring as much as 90-100 mm. 



A drawing of the living animal represents it as having very- 

 large branchiae and a wrinkled mantle edge. The complicated 

 coloration has for its basis a chocolate ground diversified with 

 bold mottlings of a lighter brown. There are also markings of 

 three other kinds : (1) blotches of opaque white, (2) small spots 

 of dark brown, and (3) ocelli with a dark centre and a white or 

 bluish circumference. These ocelli occur only on the light mott- 

 lings : the other kinds of markings are found in both the dark 

 and light areas, though naturally the dark spots are much more 

 conspicuous on a light background. The stems of the branchiae 

 are white, the perfoliations greenish but speckled with white. 

 The lower part of the rhinophores is chocolate colour ; the per- 

 foliations are darker and marked with thin white lines. The under 

 surface is of a fine clear yellow and bears on the mantle and 

 sides of the foot (but not on the sole) bold and distinct spots, 

 dark brown in colour and various in size. 



The preserved specimens are mostly of a dirty white with 

 slate coloured blotches and dots, as usual in Platydoris ; the 

 surface is finely granulated and the texture hard and stiff. The 

 integuments contain numerous spicules. They are straight or 

 slightly bent, not very large, not branched but covered with 

 lumps and granulations. The oral tentacles are digitate and 

 grooved. The foot is moderately broad (measuring 30 mm. across 

 in a specimen which has a mantle 70 mm. wide), but it has a 

 thin expanded margin and when this is turned inwards it appears 

 narrow. It is grooved in front and the upper lamina of the 

 groove is notched. The rhinophore openings are large slits but 



