20 SIR CHARLES ELIOT 



Challenger Reports, Nudibrancliiata, p. 45), but the veil is different, and the grooved 

 tentacles are, as preserved, below it ; there are more tubercles on the back, and the 

 branchiae are fewer in number. The tentacular prolongations of the lips are also 

 remarkable. Rudiments of such formations may be seen in other species, but here they 

 are unusually distinct. 



Though I hesitate to refer the specimen to T. challengeriana, it is quite possible 

 that the two species may not really be distinct.* 



Tritonia pallida, Stimpson. Stimpson, Proc. AcacL Philadelphia (1854), p. 388. 



One specimen, with the label " 8 m. N. of Dassen Island in 35 fath." (Cape Colony.) 



The animal is perfectly smooth and white ; the yellowish viscera can be seen 

 through the semitransparent integuments. It is somewhat bent and measures 35 mm. 

 in length, equivalent to at least 40 if it were straightened out. The breadth is 14 and 

 the height 12 '5 mm., the foot is 12 mm. broad. 



There appears to be no tail distinct from the body. The back is bordered by a 

 distinct dorsal margin, projecting about 2 mm., and bearing seventeen branchial plumes 

 on each side. The foot also has an expanded lateral margin and is rounded in front. 

 The middle of the anterior margin is drawn up towards the mouth, but not notched. 



The branchial plumes are of various sizes. The largest are the third, fifth, ninth 

 and thirteenth on the right, and the fourth, seventh, eighth, ninth and eleventh on the 

 left. The two or three foremost and hindmost are quite small. The largest plumes 

 stand out from the back about 4 mm., and measure 6 mm. across. The primary axis is 

 bifurcate ; each bifurcation bears two or four secondary branches, and these branches in 

 their turn bear irregular, simply pinnate projections. The smaller branchiae are from a 

 quarter to half the size of the larger ones and simpler, generally consisting of a short 

 bifurcate stem, bearing on each side two or three simply pinnate plumes. The genital 

 orifices are not conspicuous, and are situated under the fourth plume on the right side, 

 rather high up. The vent lies just under the dorsal margin, between the sixth and 

 seventh plumes. 



The frontal veil (fig. 11) is of moderate size, about 8 mm. wide and projecting 3 mm. 

 from the head, not counting the appendages. There are four of these on each side, 

 digitate, and about 3 mm. long. The veil is divided into two halves by a central curve 

 inwards, in the middle of which is a very small papilla. There are only slight and 

 uncertain traces of a tentacular groove on the outermost process. 



The rhinophore sheaths are wide and open, 2 mm. high and 3 wide, with irregularly 

 crenulate edges. The club of the rhinophores is quite simple and surrounded by about 

 ten plumes, united at their bases and of various sizes, simply pinnate or bipinnate, and 

 occasionally imperfectly tripinnate. 



* Since writing the above I have examined the type specimens of T. cliallengeriana in the British Museum. 

 They are almost smooth, whitish, and, in addition to other differences, the branchiae are more numerous, finer, and 

 more elaborately ramified than in T. appendiculata. 



(ROY. soc. EDIN. TRANS., VOL. XLI., 528.) 



