NEPHTHYS CIRROSA. 37 



Habitat. — The Channel Islands, Herm and Guernsey. In sand under stones at 

 Galway, Ireland. 



Shores of France, Dinard and Croisic (Baron de St. Joseph) ; Norway (Canon 

 Norman) ; Strait of Magellan (Ehlers). 



The head (Plate LVII, fig. 17) is longer than broad, somewhat translucent, and 

 seven-sided. The anterior border is curved between the conical tentacles, which usually 

 have a small translucent speck at their inner base. A longer pair occurs behind 

 after a considerable interval, and latero-ventral in position. 



The mouth has a triradiate outline, for between the two triangular flaps in front is 

 a fissure which runs into the transverse furrow behind. Posteriorly a striated elevation 

 occurs, which tapers off about the fourth foot. The proboscis (Plate LVII, figs. 17 and 18) 

 has twenty-two rows of rather long papillae, each row having six or more papillae. 

 Shorter papillae are distributed over the general surface. A single dorsal median cirrus 

 is present, as in A. ciliata, but it is more slender. The terminal arches of bifid papillae 

 are normal. 



The typical foot (Plate LXVII, fig. 3) has a rather long low lamella, which extends 

 outward beyond the tip, its highest point being about the centre, and thus differing from 

 that of A. Hombergii. No other flap is present. The dorsal cirrus is of average length 

 and subulate. The branchia is of moderate size and curved outward. The spinigerous 

 lobe is narrow and flattened. The fillet guarding the base of the barred bristles projects 

 as a small ridge externally. 



The inferior division posteriorly has a terminal lamella of moderate size directed 

 upward. It differs in shape, and is less developed than that of A". Hombergii. A small 

 flap, a process of the fillet guarding the base of the bristles, occurs superiorly over the 

 base of the upper bristles. The spinigerous lobe is bluntly conical and of some thickness. 

 The ventral cirrus is of considerable size. 



The capillary bristles (Plate LXXVI, figs. 12 and 12 a) have a rounded shaft 

 and a long flattened curved blade tapering to a fine point, the edge being minutely 

 serrated. Under the microscope many of these are yellow. They are comparatively 

 long and pale golden to the naked eye, with a marked curve backward. The camerated 

 bristles have a cylindrical shaft — dilating as it approaches the barred region, which 

 forms a long spindle terminating in a tapering tip (Plate LXXVI, fig. 13). The 

 crescentic fold between the feet ventrally probably indicates the opening of the 

 segmental organ. 



This form comes near A. longisetosa. 



In an example from Herm, about four inches long, the superior lamella rose higher 

 than usual, and had a different shape, since the outer edge was abrupt, and the inner edge 

 also in some was more or less steep. The inferior lobe was less developed than in some 

 examples of A. Johnstoni. A little further modification of the foot would bring this form 

 within touch of A. ciliata. 



This species and A. Johnstoni come very near CErsted's A. longisetosa 1 from 

 Greenland, the former, perhaps, most closely. 



1 ( G-ronl. Annul. Dorsibr./ p. 195, figs. 75, 76. 



