94 SIR C. ELIOT ON NUDIBRAKCHS [May 17, 



lation of the jaw varies with age. Of the six species, M. pellucida 

 seems distinct from the others, which are all nearly related to 

 M. arhorescens. M. levis is distinguished by being quite smooth 

 and not at all tuberculate. M. ramosa is closely allied to M. arbo- 

 resceiis, and diifers chiefly in having unusually large branchise and 

 appendages. M. viridescens and albo-tahercidata differ from these 

 last two forms in having branched pi'ocesses on the velum, and 

 are closely allied one to another in sti-ucture, though by no means 

 similar in external appearance. 



It is noticeable that in none of these forms is the interior of the 

 buccal cavity black, and that most of them have only one fully- 

 developed row of denticles on the jaw. 



Marionia pellucida, sp. n. 



One specimen dredged in 10 fathoms near Wasin, East Africa. 



The living animal showed very little colour but for the pink 

 liver which shone through the transparent integuments. The back 

 was sparsely reticulated with vermilion, turning to deep crimson 

 near the bases of the branchife, and also bore some opaque white 

 raised spots. The sides of the body were white and the edge of 

 the velum sandy-coloured. The velum was not bifid, and bore 12 

 processes, of which 8 were 3-branched. The branchiae were 13, of 

 modei^ate size, du-ected backwards. The finer branches very 

 delicate and ti-ansparent. 



The alcoholic specimen is yellow, with small tubercles of a 

 lighter colour on the back and sides. It is 15 millimetres long, 

 5 broad at most, and 4 high. The 13 branchife are rather far 

 apart from each other ; none are large, and the first pair as well 

 as the last three are minute. The dorsal margin is not very 

 prominent. The rhinophores are large. The velum as described 

 above, but though the outermost processes probably represent the 

 tentacles, they do not seem to be grooved as usual. The long 

 narrow jaws bear three or four rows of denticles on the edge. 

 The radula is at most 22 + 1.1.1 + 22 x 25, but many of the rows 

 are much shorter. The central tooth is not very wide and tii- 

 cuspid, the side cusps being as high as that in the middle. The 

 stomach has a circular band of about 70 small yellowish plates, all 

 of much the same size and usual triangular shape. 



Marionia levis, sp. n. (Plate IV. fig. 4.) 



Six specimens from Chuaka, East Coast of Zanzibar, and Wasin, 

 East Africa. Two were dissected.- 



The living animals were high and narrow in shape, with a flat 

 back. The sides were desciibed as white, mottled with translucent 

 patches. The ground-colour of the back was a light purplish 

 brown, with stripes of the same colour but darker and others of 

 white. The branchiae and rhinophores were pink with dark red 

 blotches. 



An uninjured alcoholic specimen is 26 millimetres long, 10 high, 

 [12] 



