90 NATURAL HISTORY OF OUR SHORES 



bristle matted into a kind of felt. It is shown in two 

 aspects in Fig. 37. 



Closely allied to it is another " Sea-mouse " (Hermione 

 hystrix). It is of about half the size of the last, and is without 

 the resplendent tints. Its colour is brown, and it is closely 

 set with fascicles of desperate barbed setae or bristles ; each 

 of these is about half-an-inch long, exceedingly sharp, and 

 slightly flattened. Their edges are barbed with many 

 sharp points, slanting backwards, for about half their 

 length. These make formidable weapons, for they are as 

 brittle as glass, and when they enter the skin of whatever 

 animal touches them they break off and leave the barbed 

 portion inserted. Each of these barbed setae is sheathed 

 between two very limp flat ones, which conceal it, but 

 crumple easily out of the way when the rigid one enters 

 the flesh of its recipient. 



Both these species are tolerably common around our 

 coasts, on muddy or partly Zostera-covered ground. They 

 may often be found by seeking in such localities at low- 

 tide limit, but are much more readily obtained by the 

 dredge or trawl. 



Closely allied to these are many other worms, all char- 

 acterised by the two rows of scales on the back. A very 

 common one is Polynoe propinqua. It is about an inch 

 and a half long by a quarter of an inch broad, of a red 

 colour, obtuse in front, pointed posteriorly. 



It may frequently be seen, on turning over stones, 

 adhering to the stone's under side, and travelling with a 

 wriggling action and great rapidity. One very pretty 

 species is Nykia cirrosa. It is larger, and much wider in 

 proportion, than the last, of a cream-colour, or nearly 

 white, and resplendent with pearly tint. This species is 

 figured in Plate 36. 



Sigalion boa is, like the Polynoes, etc., scaled down the 

 back, but of more typical worm form, being about five 



