NEPHTHYS GMGA. 13 



serrate bristles (Plate LXXVI, fig. 1), which extend outward fully three times the longer 

 diameter of the fan. The serrated edge, simple in lateral view, presents a close series of 

 transverse spikes (Plate LXXVI, fig. d) as indicated by various authors. Beyond the 

 serrated region the bristle extends as an extremely attenuate process and tapers to a fine 

 smooth point. A narrow fleshy ridge with the tip of the spine projecting externally 

 next follows with a row of the pale barred tapering bristles in front. These show a series 

 of transverse bars (Plate LXXVI, fig. 1 b, and c, c 1 ) which in lateral view (d) have an 

 interrupted edge. The bars are probably modifications of transverse rows of spikes — 

 forming the so-called camerated arrangement. Dr. Thomas Williams was thus incorrect 

 in saying that one of the rows of bristles is placed in front and the other behind the cirral 

 lamina. 



The foregoing constitutes the dorsal division of the foot, and it is separated by a 

 considerable interval from the ventral division, the intermediate region being occupied by 

 the branchial process. 



The inferior lamella is broadly lanceolate, pointed, and with the longer edge ventral- 

 ward. It is continuous with the fleshy lobe, the tip of which slopes from below upward 

 and outward, the reverse of the arrangement in the upper lobe. The fleshy part 

 terminates superiorly in a thickened adherent point. The long pale bristles similarly 

 pass out close to the base of the lamella, and extend about the same distance. A narrow 

 fleshy ridge (corresponding to the foot proper) separates them from the row of barred 

 bristles in front. The conical ventral cirrus is slightly flattened and of moderate size. 



In the posterior feet both dorsal and ventral lamellse, branchiae, and dorsal and 

 ventral cirri diminish as in iV. Rombergii (Plate LXVI, fig. 8), and in the last feet only 

 a minute trace of the cirri remain. The bristles also decrease in length but retain the 

 same fundamental arrangement. 



The body terminates in an anus, with a median cirrus ventrally. 



Loxosoma3 were studded on the branchiae of a large example sent from Montrose 

 Bay by the late Dr. Howden. De Saint Joseph mentions Cothurnia maritima as common 

 on the bristles of those at Dinard, and a form probably identical is found at St. Andrews 

 and elsewhere, in great numbers, on the same organs; indeed Infusoria are very 

 frequently found parasitic on the Nephthydidee. 



A form (Var. ciliata, Plate XLIII, fig. 2) which approaches N. caeca in the 

 feet, and which may be Dr. Johnston's A", longisetosa, occurs at St. Andrews and 

 Montrose occasionally in May and June. The largest examples were about six inches long, 

 and they ranged from this downward to two or three. In structure the foot (Plate LXVI, 

 fig. 3) has longer divisions, a long, narrow dorsal cirrus, and the superior lamella is 

 slightly less. The length of the slender bristles, which give a remarkably hairy appear- 

 ance and great breadth to the animal, is diagnostic. The foot generally agrees with that 

 of N. cd3ca, but the superior lamella is often distinctly less and does not project so far 

 outward. The spinigerous region, moreover, ends in a more distinctly rounded flap than 

 in the ordinary form— projecting outward above (and in front of) the dorsal cirrus. No 

 special differentiation occurs in the fleshy parts of the inferior lobe, although the upper 

 part of the fillet from the barred bristles is somewhat more distinct. The bristles consist 



