JAPANESE NUDIBEAXCHS. 9 



Neither portion is much lobed or branched. The central nervous 

 system is much concentrated and is enclosed in a thick capsule 

 which hides even the eyes. 



The labial cuticle bears two yellowish plates composed of 

 rods which are not distinctly bifid though the edges are some- 

 times jagged. The radula is deeply grooved in the middle, but 

 when it is spread out, the rhachis is seen to be wide. The 

 teeth are large, transparent, yellow and simply hamate, bearing 

 a ridge on the inner side but no denticles. The innermost are 

 small, the outermost small and slender. In two specimens examined 

 the number of rows was only 20 and 24 respectively, and the 

 number of teeth in a row was in both about 40. 0. 40. The 

 shortness of the radula is characteristic of the species. 



The hermaphrodite gland is distributed over the liver in the 

 usual way. Both its duct and its ampulla are long. The 

 spermatotheca is large. A large prostate is present but no trace 

 of armature was found in the genitalia. 



Halgerda japonica sp. nov. 



Sse Bergh on Aporodoris rubra in Siboga Expeditie, Opisthobmnchiata, p. 94. 



(Plate I., fig. 2). 



One specimen from Misaki, 44.5 mm. long and 27 mm. broad. 

 It is accompanied by a coloured drawing which represents a 

 flattish Dorid with a delicate and complicated colouration composed 

 of various shades of grey. The ground colour is a yellowish 

 grey which is lighter and brighter at the mantle edge where it 

 forms a not very distinct border. Over the dorsal surface are 

 distributed roundish areas of a darker grey, varying in intensity, 

 and about 4 mm. in diameter. Small white dots are scattered 

 over the whole dorsal surface regardless of these markings, and 

 in one or two places are aggregated into white spots of a fair 

 size. The six branchiae are represented as large, whitish and 

 very delicate. The underside, which is shown at one point, is of 

 a drab colour, with minute black dots on the side of the foot. 



The preserved specimen has not retained these colours. It 

 is soft and presents various shades of light and dark brown 



