528 SIR CHARLES ELIOT ON. THE NUDIBRANCHIATA 
Challenger Reports, Nudibranchiata, 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 
branchiz 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 TZ. challengeriana, it is quite possible 
that the two species may not really be distinct.* 
Tritoma pallida, Stimpson. Stimpson, Proc. Acad. 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 
bifureate ; each bifurcation bears two to four secondary branches, and these branches in 
their turn bear irregular, simply pinnate projections. The smaller branchiee 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 pimnate plumes. The genital 
orifices are not conspicuous, and are situated under the fourth plume on the right side, 
rather high up. The vent les 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 
erenulate 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 7. challengeriana in the British Museum. 
They are almost smooth, whitish, and, in addition to other differences, the branchiz are more numerous, finer, and 
more elaborately ramified than in T. appendiculata. 
