XEPHTHYS JOHNSTONI. 35 



Habitat. — Southport Sands (Dr. Carrington) ; West Sands, St. Andrews, after 

 storms (E. M.) ; St. Magnus Bay and Balta, Shetland (J. Gr. J.); 'Porcupine,' 1869, 

 85 fathoms, on " Porcupine Bank," off Ireland. 



Greenland (CErsted). 



The head (Plate LVII, fig. 15) has a broad and slightly convex anterior border 

 with the slender and tapered tentacle at each angle. A feature, apparently not 

 unfrequent, is the presence of a translucent, oblique, elongated patch at the inner base 

 of this tentacle. The second tentacle is broader, with a pointed tip, and occurs after 

 a considerable interval. Posteriorly the elongated head terminates in two flattened 

 lobes with a slight median furrow. A sense-papilla occurs at each side. The lips 

 (Plate LVII, fig. 16) inferiorly approach the type of A 7 . Hombergii, but the filament is 

 longer, and the arrangement of the furrows is different. The latter, however, is not 

 of much value. 



The body has the usual shape and terminates posteriorly in the somewhat short 

 anal cirrus (Ehlers). 



The proboscis has rows of rather long papillae distally, about six in each row, and 

 besides, a long median cirrus both dorsally and ventrally just beyond the rows. There 

 are y£ bifid papillae guarding the aperture in the distal region, and the gap between 

 them has a single simple papilla. 



The first bristled foot has its dorsal fascicle directed upward and the tips turned 

 backward, the whole forming a prominent fan. No dorsal cirrus is present, but the 

 ventral is long, lanceolate, and pointed. 



The typical foot (Plate LXVII, figs. 2 and 2 a) has considerably longer bristles 

 than in N. ciliata. The dorsal lamella has a similar curvature to that in N. ciliata, but 

 has, in addition, a small and inconspicuous accessory lobe beyond its diminished outer 

 end — continuous with the base of the cirrus. The spinigerous region forms a prominent 

 ridge and ends externally in a smoothly rounded border without the distinct lobe as 

 in N. ciliata. The fillet at the base of the barred bristles is distinct but does not rise 

 into a flap. The dorsal cirrus is a filiform process, though this does not seem to be an 

 important character, since, as in the dorsal lamella, considerable variety exists in the 

 same specimen. The branchia is not large, and is curved externally. 



The lower division has a large posterior lamella, often sinuous inferiorly and of a 

 broadly ovato-lanceolate form. The setigerous flap is oblique externally, and the fold 

 running from the base of the barred bristles presents a flap superiorly. 



The capillary bristles both dorsally and ventrally are comparatively long but have 

 very minute serrations (Plate LXXVI, fig. 10), a feature when contrasted with such as 

 occur in N. longisetosa. The serrations, moreover, are limited only to the lower region 

 of the bristle, the long tip being bare. In the camerated 1 bristles (Plate LXXVI, 

 fig. 11) the transverse bars proceed far downward, the widest region of the bristle being 

 thus included in the camerated part. When contrasted with those of N. longisetosa, 

 they are considerably shorter and smaller. The ventral cirrus is lanceolate, larger than 

 in N. ciliata, but considerably less than in N. longisetosa,. 



1 So termed from the peculiar arrangement of the rows of spikes. 



