366 PERCY SLADEN TRUST EXPEDITION. 
The broadly ovate head bears two pairs of rather ill-defined eyes, of which the 
anterior are rather larger. The median tentacle appears to be short and slender; the 
lateral tentacles being of the same length, dilated but with a pointed termination, 
while the palps are longer and slender throughout. 
The small size of the branchiz is noticeable, and their appearance is in contrast to the 
ramifying tufts of H. carunculata. The branchiz begin on the first body-segment and 
consist of inner and outer divisions, the latter being larger, which divide at once into 
short club-shaped terminal branches. These are brown with white tips, and are greatest 
in number on the anterior segments (50 on the fifth segment), and diminish until there 
are only 3 on the last segment. 
Attention has already been drawn to the well-developed dorsal setee, which rise in a 
compact bundle fiom the well-marked setigerous prominence. Two kinds of sete are 
represented: one long, very slender, gently tapering, which, unlike the similar kind in 
H. carunculata, never possesses roughened tips; and another much stouter and shorter 
kind, hollow up to the apex and symmetrically tapering to a blunt point. This possesses 
a row of very numerous serrations (more than sixty) along one side. The dorsal cirrus 
is two-thirds the length of the dorsal tuft of setae and is composed of a swollen basal and 
filiform terminal portion. The ventral sete are not half the length of the dorsal tuft, 
and are much coarser than those described above. There is but a single type, a stout 
bristle not tapering markedly but ending in a slightly curved hook-like tip. The setze 
may be smooth or possess a series of rather faint serrations under the tip varying in 
number up to 12. A very striking difference is presented compared with the strongly 
serrated sete of H. carunculata, which, moreover, possess a pronounced spur below the 
region of serrature, which is here absent. 
Locality. Ile du Coin, Peros, Chagos; a single specimen. ‘Sand under loose 
coral masses.’ (See note on p. 371 for additional localities. ) 
11. Lucarunculata grubei, var. gracilis, var.n. (Plate 46. fig. 11.) 
Measurements. Length 28 mm., breadth 4 mm.; no. of segments 41. 
This is a much smaller and slenderer form than the preceding, but the similarity of 
the scheme of colour-markings is rather striking. The ground-colour is a greyish 
brown and the large development of yellow pigment on the dorsum gives a rather 
silvery coloration to the animal as a whole. The ventral surface is beset with spots of 
light pigment. The dark striz remarked in the foregoing description are equally 
prominent here. 
The caruncle is rather smaller, being attached to the first and second body-segments 
and reaching to the middle of the third segment only. It is of a compact and regular 
form, ovate and broader anteriorly; but the breadth is always distinctly less than the 
length. There is a very definite median axis expanding into a heart-shaped tract 
anteriorly, and lateral regions consisting of five or six folds respectively, on the two 
sides. The folds are entirely separate from one another, and are deep narrow lamellze 
which subdivide with pinnate branching. The connection of the first fold on either 
side with the median axis is not plainly shown. The whole structure is of a dark brown 
colour with yellow spots. 
