xii NEREIDIFORMIA 317 



breadth occurs at the segments immediately following the head. 

 Further, the palps are long, the peristomium is twice as long 

 as the next segment, and the back of the worm is strongly- 

 arched At all depths on rocky and stony ground. Northern 

 coasts. 



N t (Nereilepas) fiicata Sav. lives in the topmost whorls of 

 empty whelk shells and in those occupied by hermit crabs. The 

 ground colour is tile-red, with two milk-white bands along the 

 dorsal surface. The dorsal lobe of the foot is slightly foliaceous, 

 glandular, and vascular. 



JV, (Alitta). virens Sars, is a giant amongst Polychaetes, reach- 

 ing a length of 1 8 inches. Its name suggests its colour ; it is 

 very plentiful at certain times at St. 

 Andrews, and between tide -marks along 

 the shore of the Mersey estuary, as well 

 as elsewhere. It forms a burrow in the 

 clay, etc., of the shore, and lines it with 

 mucus, which is abundantly secreted by 

 the great foliaceous lobes of the parapodia. 

 These great leaf- like lobes of the foot recall 

 the modification which the foot of many 

 species of Nereis undergoes in transforma- 

 tion into Heteronereis : they are so greatly Fig. 169. Parapodram of 



d J N. wrens Sars. x 4. a, 



developed that, at first sight, the worm . Notopodial cirrus ; b, 

 might be mistaken for a large Phyllodoce. ^f 1 1 ; ^3 

 The worm is known as the " Creeper," cirrus ; 1, foliaceous ap- 

 and is much esteemed as bait on some pen age " ( lom ^ erb *' 

 parts of our coast. 



Fam. 7. Nephthydidae. The elongated body is quadrangular 

 in section, the dorsal and ventral surfaces being almost flat. (For 

 head see p. 262, and for parapodium, p. 264.) The two lobes 

 of the parapodium are widely separated, and each is fringed with 

 a membrane, while a sickle-shaped " gill " hangs down from the 

 under surface of the notopodium. The pharynx is enormous. 

 Of the genus Nephthys two species, called the " Lurg " or " White 

 Cat " by fishermen, occur on our coasts. Their active movements 

 and beautiful mother-of-pearl tint are characteristic. N. liom- 

 hergii Aud. and Edw. occurs on the shore, and down to 20 

 fathoms ; it is 3 or 4 inches long, and may be found burrowing 

 in the sand ; the chaetae exceed in length those of X. caeca 



