Dr. Johnston on the British Aphroditaced*. 435 



with lighter and dark shades ; belly perlaceous, with a red 

 central line from a blood-vessel appearing through the skin : 

 head mostly concealed by the anterior scales, cordate with an 

 impressed line in the middle, pink-coloured or reddish, with 

 four eyes placed wide asunder: antennce three, the medial 

 largest, all bi-articulate, swollen near the apex, which is acutely 

 pointed : palpi two, setaceous with a suddenly acuminated 

 point, paler coloured, stouter and twice as long as the antennas, 

 somewhat annular : tentacular cirri two pairs, similar to the 

 medial antenna, the bulb ringed with black, the acute points 

 pale : scales fifteen pairs, imbricate, ovate or kidney-shaped, 

 the anterior nearly circular, variously coloured and dotted, 

 convex towards the centre, smooth to the naked eye, but really 

 roughish with scattered short spines or processes visible only 

 in certain lights or near the margin ; they are attached to the 

 2nd, 5th, 6th, 7th, 9th, 11th, 13th, 15th, 17th, 19th, 21st, 

 23rd, 26th, 29th, and 32nd segments by mammillary tuber- 

 cles, considerably larger than the alternating branchial ones, 

 and when removed the back appears spotted over the base of 

 the feet, the spots becoming quite distinct and regular near the 

 tail, which is terminated by two styles : superior cirri eighteen, 

 bulbous near the apex, which is pointed, with a dark ring at 

 the bulb and blackish about the base : feet thirty-six pairs, 

 each with a small inferior cirrus and garnished with numerous 

 straw-yellow bristles, those of the dorsal branch shorter than 

 those of the ventral, all slightly bent near the apex, which is 

 minutely serrulate and acute : spines simply conical. 



The animal moves quickly by means of its feet in a some- 

 what undulating manner, the medial antenna being held erect 

 and reverted, the palpi stretched forwards and inclined to the 

 ground, which it examines by their aid. When thrown into 

 fresh- water it dies almost instantly, and the scales drop oif; 

 and even during life these organs are removed with so slight 

 a friction that it is not easy to take up a specimen without de- 

 priving it of one or more of them. 



Of his Aphrodita Lepidota Pallas says, ff Certe in mari inter 

 Angliam et Belgium satis copiose occurrit haec species, et ex 

 fascia plerumque longitudinali nigra facile adgnoscitur." A 

 Polynoe marked in this fashion is common on our shore, which 



2 G 2 



