32 NEPHTHYS LONGISETOSA. 



The head is less rounded in front than in A r . cseca, and the anterior tentacles more 

 prominent and larger. 



In what appears to be the northern variety of this species from Finmark the dorsal 

 lamella is smaller, the accessory lobe little developed, the dorsal cirrus shorter and 

 broader, the branchia much larger, but still rolled inward, the ventral lamella much less 

 and the cirrus smaller and less foliaceous. The bristles in this form are more slender 

 than in the British, but the serrations are distinctly separated. The barred forms are 

 also more slender. While the lamella both dorsally and ventrally are thus smaller, the 

 setigerous region in both divisions is more prominent and acute. 



A form dredged by Canon Norman near Bergen in 1878 differs from the foregoing 

 in the much darker bristles, which have, however, the same backward curve. The body 

 somewhat resembles that of K cseca, though the specimens are smaller. The head shows 

 in one of the preparations two opaque specks posteriorly, but they do not seem to be eyes. 

 The proboscis is enclosed. The foot presents a considerable dorsal lamella of a rounded 

 form and extending to the tip. In front of it are the dark capillary bristles, then a much 

 less spinigerous region than in N. longisetosa so that the barred bristles are quite close to 

 the others. What is, however, the most marked feature is the presence of a small rounded 

 flap superiorly and inferiorly in front of all the bristles, and this is apparently a develop- 

 ment of the fillet in front of the barred bristles. The dorsal cirrus is small instead of 

 large, and separated by a slight notch from the branchia, which is large, though not long, 

 and curved outward. The inferior division has a somewhat smaller posterior lamella 

 than K longisetosa, and the cirrus is much less — forming a simple conical process. Both 

 kinds of bristles appear to be more slender than in N. longisetosa, but the larger size of 

 the latter probably makes the difference more pronounced. 



The foot thus differs in the shape of the dorsal lamella, which is somewhat higher 

 than in the example from Finmark, and in the pointed nature of the superior lobe. The 

 dorsal cirrus and branchia are similar. The ventral lobe is also acutely pointed. The 

 ventral cirrus is acute, and the long curved bristles have remarkably distinct serrations. 

 The specimens are small and imperfect. 



Nephthys longibranchiata, of the ' Porcupine ' Expedition, differs from the allied form, 

 N. longisetosa, (Erst., by the broader and less elevated superior lamella, by the shorter and 

 more obtuse process at the base of the branchia, by the greater size and length of the 

 branchia, by the rounded tip to the inferior lobe, the projection of the spine-tip, and the 

 much smaller inferior cirrus. 



Malmgren (1865) considered that GErsted had this species in view in his ' Gronlands 

 Annulata Dorsibranchiata,' but the figures are so unsatisfactory that doubt must always 

 remain. He certainly describes the dorsal lamella as triangular. Malmgren also (1867) 

 pointed out that the specimens so labelled in the British Museum by Dr. Johnston, from 

 Berwick Bay, Holy Island, and the Firth of Forth, pertained to Nephthys Hombergii 

 and a new species. 



Such forms as Nephthys phyllocirra, Ehlers, 1 make a close approach to this species. 



1 c Florida Annel./ p. 131, Taf. 38, fig. 7—11, 1887. 



