3 I O POLYCHAETA 



and are mostly found under stones at low tide. Some species 



have a very wide geographical range. 



Polynoe.^ The body is short ; none or only a few segments 



at the end of the body are uncovered by the elytra, except in 



the long body of P. johnstoni. 



A. With twelve pairs of elytra. In P. squamata Linn, the 



elytra entirely cover the 

 body and conceal the 

 head, each elytron over- 

 lapping the next poste- 

 rior one, and those of the 

 two sides overlapping. 

 General colour sandy- 

 brown, speckled, lighter 

 or darker. The fringed 

 elytra are very firmly 



Eco. 182,-Elytra, A, of Polynoe squarmta L.; B, of fixed to the bod The 



P. clava Mont. x 10. , Area of attachment ; . * 



e, external margin ; /, fringe (the letter is at the notopodial chaetae 



P r J ecfc fr m 



below the elytra. The 

 worm is common between tide-marks and in the coralline region, 

 is about one to one and a half inches in length, and about one- 

 third of an inch in width. Atlantic. P. clava Montagu, may 

 attain a larger size, though it is generally smaller. The elytra 

 are dark, usually grey, mottled with white or light grey, un- 

 fringed, and do not overlap to so great an extent as in P. squa- 

 mata, so that the middle of the back and the hinder part of the 

 body is more or less exposed. This is never the case in the pre- 

 ceding species, but even here it is subject to variation in extent, 

 depending on the amount of food contained by the worm or on 

 the ripeness of the genital products. It occurs in the Mediter- 

 ranean. 2 



R With fifteen pairs of elytra. P. imbricata L. is probably 

 the commonest species of the genus, occurring nearly every- 

 where under stones at low tide. It is about an inch in length ; 

 the elytra are deciduous, and are very variously coloured and 

 marked ; sometimes uniformly grey or even black, sometimes 



1 Herein arc included the various genera formed by Kinberg, Malmgren, and 

 others. 



2 It appears to be the same as P. grubiana Clap. 



