REPORT OH THE NUDIBRANCHIATA. 
37 
foot beneath by a furrow, and from the dorsal portion of the body by a shallow groove 
behind the rhinophoria. The anterior extremity slants steeply downwards and back- 
wards. The mouth (fig. 13, a) is provided with a pair of thick lips, which unite above and 
are connected below by a transverse piece ; internally are a number of folds and furrows 
which converge to the wide mouth opening. On the side of the head, not far from the 
lips, are the peculiar tentacles (fig. 13, h), from fifteen (on the right side) to sixteen (on the 
left) in number, almost cylindrico-conical in shape, and measuring about 2'5 mm. in length; 
these are arranged in a double or triple series, and take their origin from a low crescentic 
basal piece wdiich is a little higher behind. Behind these are the obliquely situated 
powerful compressed rhinophoria (fig. 13, c), which are attached to the “neck” and very 
close to each other. From the long but narrow base the powerful stalk takes its origin, 
which at its upper end is slightly broader and thicker (breadth 7 mm., thickness 3 mm.) ; 
the outer portion of the stalk ends in the rhinophore proper, while the inner part (fig. 
13, d) is continued upwards into the papillary portion. The rhinophore has the customary 
sheath -with its three finger-like processes (fig. 13, c, and fig. 14); these all measure about 
3 mm., and are rather flattened. The club of the rhinophore is some 3 mm. high, and has 
40 or 50 broad leaves on both sides. 1 The upper margin of the papillary part has four 
compressed points, of which the outermost but one is the largest. The eyes are not visible 
from the exterior. The dorsal surface is for the most part rather broad, and is narrower 
at the posterior extremity only ; it is rounded and not marked off from the sides of the 
body. From the margin of the back spring the five strong branchia-bearing papillae; 
the distance between the rhinophoria and the first pair of papillae is rather long, nearly 
as long as the distance between the first and second pair of papillae, or the second and 
third ; the distance between the third and fourth pairs is a little shorter, and soon after 
this follows the fifth pair. The papillae are situated almost exactly opposite each other ; 
only the fifth on the right side is somewhat further back and also smaller than its fellow 
on the left side ; in other respects the two corresjtonding papillae were nearly of equal 
size. In the middle of the first inter-papillary space (a little nearer to the second papilla), 
near the right dorsal margin, is the slightly prominent anal papilla , in front of which is 
the fine renal pore. The papillae are rather sharply differentiated from the dorsal wall, 
on which they are set somewhat obliquely ; each papilla is separated from its fellow by a 
rather narrow space, which in the case of the fourth papilla has quite disappeared. The 
first papilla (PI. VIII. fig. 1) is a little compressed, and continuous above with the 
three likewise rather compressed finger-like processes, of which the middle one is the 
largest. Above the base, in the neighbourhood of the anterior and posterior margins on 
the outer side, is a small branchial tuft, protected by a cylindrical finger-like process ; 
similarly on the inside, but rather higher, are tufts, but without a covering. The branchiae 
are irregularly tri- and quadri-pinnate, and are provided with a short stem ; the leaves 
1 Bergh, Malacolog. Untersuch., loc. cit., p. 290, Taf. xxxvii. fig. 13. 
