xii NEREIDIFORMIA - APHRODITIDAE 3 I I 



mottled with brown: in other specimens each elytron has its 

 outer half pale or white, while its inner half is darker, usually 

 some tint of brown or olive green, so that the worm appears 

 to have a dark band along the middle of its back. Other 

 patterns occur. The body is entirely covered by the elytra. The 

 chaetae project considerably, and are nearly as long as half the 

 width of the body ; those of the notopodium are brown and are 

 directed upwards, being nearly as long as the 

 golden neuropodial chaetae. This species has a 

 very wide range, occurring on both sides of the 

 Atlantic, even on the shores of Nova Zembla, 

 and reappearing again at Japan. P. semi- 

 sculptus Leach is rather larger than the fore- 

 going. The elytra are very readily detached: FlG 16 3.1^ y t ronof 

 they are light in colour, without a fringe, but Poiynos imbri- 

 with large papillae near the margin. The SStoS^f* 8 * to 



notopodial chaetae are thicker than those of the bod y ; outer 



, . nil i border ; t, inner 



neuropodmm. Several other species are also border. 

 common, but P. johnstoni v. Marenz. 1 differs from 

 the rest in having an elongated body of some seventy segments, 

 so that the posterior half is uncovered by the elytra, which are 

 small, greenish-grey, speckled, and have no fringe. It is common 

 and widely distributed, but appears to be only found in the tubes 

 of Terebella nebulosa. 



C. With eighteen pairs of elytra. P. gelatinosa Sars, may 

 attain a length of 2 inches. The elytra are very faintly coloured, 

 transparent and soft, attached by rather long peduncles. In 

 spirit they become swollen and folded, giving the worm a very 

 untidy appearance. The prostomium is partly overlapped by 

 a peculiar collar-like fold of the peristomium. 



D. With numerous pairs of elytra. Lepidasthenia has a very 

 long body, consisting of more than eighty segments. The elytra 

 are quite small, and occur throughout the body on the usual 

 segments. There are no notopodial chaetae. L. elegans Gr. is 

 a very elegantly marked worm, which, however, has not been 

 recorded from the British area ; it occurs in the Mediterranean 

 (see Fig. 156, p. 293). 



Sub-Fam. 2. Hermionina. The body is short, oval and de- 



1 Marenzeller has shown that Johnston's P. scolopendrina is not identical with 

 that of Savigny, and suggests the above name for it. 



