312 



POLYCHAETA 



pressed ; the particularly strong notopodial chaetae are directed 

 upwards and backwards so as to protect the elytra. The neuro- 

 podial chaetae are also strong. The prostomium carries a single 

 tentacle and two long palps ; the prostomial ridge may be well 

 developed. The peristomium is chaetigerous, with long cirri. 

 The jaws are represented merely by thickened prominences. 



Aphrodite. The fifteen pairs of elytra, arranged as in Polynoe, 

 are concealed by a " felting " of hair-like chitinous threads arising 



from the notopodium (Fig. 139. 



p. 268). A. aculeata L. The 

 " sea-mouse " is one of the most 

 beautiful of the Polychaetes. 

 The small tentacle is very 

 readily detached; the palps are 

 very long ; the parapodia of the 

 peristomium are directed for- 

 wards so as to form lateral lips ; 

 and its cirri are not especially 

 modified (see Fig. 132, p. 260). 

 The body, which measures 3 to 

 6 inches, consists of thirty-five 

 to forty segments, and is broad- 

 est in the middle, the last 

 dozen segments being very 

 small ; the body terminates in 

 a point. Some of the noto- 

 podial chaetae are brilliantly 

 iridescent, and give the worm 

 its characteristic coloration. It 

 is fairly common in the coral- 

 line regions, and is frequently 

 thrown ashore after storms. 

 Atlantic and Mediterranean. 



Fig. 164. Aphrodite aculeata L. (from Regne J n Hermione the "felt" is 



Animal). Nat. size. c, Neuropodial , . , 



chaetae ; p, palps ; 1, iridescent bristles ; absent, SO that the elytra are 



2, stiff chaetae ; 3, felting bristles of noto- eX posed. H. hystrix Sav. OCCUrs 



podinm. . . ~ 



m ten to thirty latnoms ol 

 water all over the British area and Mediterranean. It resembles 

 in its general appearance a fat Polynoid, with strong chaetae. 

 Laetmonice jilicornis Kinb. also occurs on our north-west coasts, 

 and L. producta Gr. has been dredged in 500 fathoms off the 



