NEPHTHYS LONGISETOSA. 29 



curved outward. The bristles are similar in curvature to those of N. Hombergii, but 

 are more translucent (thinner), and the serrated edge is less rigid, and often disappears, 

 apparently by friction. The barred bristles offer no feature of note. The inferior 

 division has a small lamella posteriorly, another nearly as prominent formed by the 

 fillet for the barred bristles, while the conical spinigerous lobe lies between. In many 

 views, therefore, the tip is trifid, and quite diverges from that of JSf. ciliata. 



The foot of the Mediterranean examples agrees with that in the Irish forms, the 

 only difference being the greater distinctness of the spinigerous papilla between the 

 lamellge in the upper division, but as the Irish specimens are badly prepared and 

 preserved this may be more apparent than real. The bristles of those from the 

 6 Porcupine ' are certainly longer. In both their colour is dull yellow, and their structure 

 seems to agree. 



The branchial process, which is of moderate size, has a well-marked papilla or 

 process at its outer base ; as shown for instance in Malmgren's figure of N. assimilis, 

 (Erst. 1 It is, however, more distinctly defined than the latter. 



This form approaches N. ciliata in the structure of the foot, yet differs in the longer 

 dorsal lamella (which thus extends further outward), in the form of the dorsal cirrus, and 

 in the basal process of the branchia. The terminal lamella of the foot is different. 

 The median dorsal cirrus of the proboscis also seems to be longer. It is no nearer 

 N. cirrosa, Ehlers, from which it differs in the great width of the dorsal lamella. 



A Norwegian example collected by Canon Norman shows a more distinctly bilobed 

 fillet in front of the camerated bristles superiorly. 



A variety procured in the ' Porcupine ' east of Cape de Gatte, nine miles from shore, 

 in 6 to 160 fathoms, had more slender bristles, which apparently had undergone some 

 change and had. lost the serrations on the edge. 



5. Nephthys longisetosa, (Ersted, 1842. Plate LVII, fig. 10-12; Plate LXVI, fig. 11- 

 foot; Plate LXXVII, figs. S-8b— brist. 



Specific Characters. — Head somewhat shield-shaped ; the anterior tentacles marked 

 by a translucent stripe at the base in front, long and slender ; second pair also long and 

 lanceolate. Proboscis distinguished by fifteen (Theel says fourteen) rows of numerous 

 papillse, viz. eleven to fifteen in each row. Dorsal lamella of the foot elevated and 

 prominent (triangular, (Ersted), with an accessory rounded process. Dorsal cirrus large 

 and lanceolate, closely connected with the base of the branchia, only a shallow notch 

 intervening, and the branchia is often curved inward. Ventral lobe with a tongue- 

 shaped lamella above the dorsal edge at the tip, and only a narrow lamella beyond the 

 foot. Both barred and serrated bristles are yellow or brownish with a metallic sheen, 

 and largely developed, the latter presenting a gentle curve from base to apex, the 

 minute spines being traceable from the short shaft to the tip. 



1 Op. cit., Taf. xii, fig. 19 6. 



