JAPANESE NUDIBEANCHS. 33 



out interruption. The foot is broad. Its anterior margin is 

 thickened and more or less grooved, the depth of the groove 

 varying greatly. In no specimen however is the margin split in- 

 to two distinct laminae. The mouth is a slit in this margin and 

 above it are two ridge -like tentacles. 



Internally the buccal parts are as usual in the genus. There 

 is a large bilobed yellow gland beneath the buccal cone. The 

 central nervous system is orange- coloured and the alimentary 

 tube describes a complete circle behind it. 



The pericardial gill is not much developed. The hermaphro- 

 dite gland is yellowish and is concentrated more than usual on 

 three or four points of the anterior liver, though it cannot be 

 detached. Eoth the spermatotheca and spermatocyst are spherical 

 and grey, but the former is considerably the larger. The prosta- 

 tic portion of the vas deferens is long, reddish and bent several 

 times on itself. The lower portion of the vas deferens and the 

 glans aro thickly armed with minute spines. These have a fairly 

 broad basis from which rises a hook or spine of rather irregular 

 and varying shape. 



These specimens are larger than those of D. rubra which I 

 have examined from other localities and they have not either as 

 preserved or in the drawing the rosy tint which usually marks 

 the species. But Alder and Hancock say that it sometimes 

 attains a length of 3 inches and variations of colour are also 

 recorded. Therefore although these Japanese specimens look to 

 me unlike those which are commonly found on the coasts of 

 East Africa and South Asia I do not think there is sufficient 

 ground for considering them a new species. But they certainly 

 constitute a well marked variety, characterized by its large size, 

 large black blotches, and probably by the ground colour being 

 brownish brick-red rather than rosy. 



Doridojiis nigra (Stimpson). 

 (Plate II., fig. 13). 

 This species is common in Japan and is represented in a 



