172 NEPHTHYACEvE. 



2. N. longisetosa, feet with the branches wide apart, the margin of 

 the intermediate space even ; dorsal branch with a cirrus, the 

 lamella dorsal, oblong, scarcely overreaching the apex ; lamella of 

 the ventral branch directed obliquely upwards, oblong, with an 

 obtuse rounded apex ; bristles long, protruded far beyond the 

 lamella, setaceous, serrulated on the outer half on one side. Length 

 3-4" ; breadth 2'". 



Nephthys longisetosa. Oersted, Groenl. Annul. Dorsibr. 43. f. 75, 76. 

 Grube, Fam. Annel. 53. 



Hab, The littoral region. 



Desc. Worm linear-elongate, narrowed insensibly from the head 

 to the tail, somewhat convex on both dorsal and ventral surfaces, 

 smooth, the median portion highly perlaceous, the sides of a uniform 

 greyish-white or wax-yellow colour. Head small and indistinctly 

 defined, forming a central lobe tipped with four small antennae ; the 

 post-occipital segment dilated on each side, mammiform, with a small 

 tuft of blackish bristles in the centre of each rising. Mouth large, 

 in the ventral side of the post-occipital segment, transverse, with a 

 prominent anterior lip ; the proboscis ventricose or urceolate, rough 

 near the top, with numerous spinose papillse, while a close series of 

 erect ones encircle the orifice. Rings very numerous, narrower than 

 their diameter, similar ; the feet prominent on each side, alike, but 

 most developed near the middle of the body, and then about as long 

 as half the diameter of the ring. Feet with their branches widely 

 separate ; the superior with an obtuse setigerous papilla, to which is 

 attached, on the upper side, an oval foliaceous lamella, and on the 

 under side, near its apex, a sickle-shaped cirrus, with a short spur 

 and small sinus at its insertion. Inferior branch rather longer than 

 the superior, lobe-like, obtusely pointed, tipped with an oblong 

 foliaceous lamella as long as the setigerous process itself; the inferior 

 cirrus short, setaceous, swollen at its base. The space between the 

 branches is greater than the length of either branch of the foot, and 

 its outline is concave or almost straight. Each branch is armed 

 with two spines of a light brown colour, and with a spreading 

 fascicle of numerous delicate bristles, which are dusky or black to 

 the naked eye. When highly magnified they appear colourless and 

 crystalline, and are so weak that they easily bend or assume a wavy 

 outline. There are three kinds of them : the first is simple, long 

 and unequal, cylindrical and smooth at the base, bulging out a little 

 above it, and thence gradually tapered to a long setaceous point, the 

 inner edge from the bulging upwards being denticulated in the most 

 minute and regular manner (PI. III. fig. 9). The second kind is 

 equal to the first in length and size, and similar in shape and in the 

 manner in which it is serrulated ; but it is jointed near the commence- 

 ment of the bellying, and the joint is like the separation of a rod 

 that has been spliced (PI. IV. fig. 11). The third kind is very 

 short, simple, setaceous and straight, serrulated on all sides, and 



