308 POLYCHAETA CHAP. 



of cirri. Mediterranean, Atlantic, on the Norwegian coast, off 

 Spitzbergen, and on the Madeira coast. S. armillaris Mull, is 

 very common at low water ; it is pale yellowish-brown, with a 

 couple of dusky marks on each segment ; and measures 2 inches. 

 The dorsal cirri are quite short, consisting of only eight to ten 

 joints. In Pionosyllis the tentacles and cirri are not monili- 

 form ; a single dorsal tooth. P. tnalmgreni M'L under stones. 

 Sphaerosyllis. The dorsal cirri are swollen at the base, and 

 are not moniliform ; the long palps are fused along nearly their 

 whole extent. S. hystrix Clap, is only about one-eighth of an 

 inch in length. Exogone Oerst. Grubea Qfg. 



Autolytus. The small palps are entirely fused with the 

 prostomium; the pharynx, which is bent upon itself, is armed 

 with a circle of denticles. Dorsal cirri somewhat foliaceous. 

 There are no ventral cirri. The male and female differ from one 

 another and from the asexual " stock " (see p. 279). A. pictus 

 Ehl. is abundant under stones. It measures about two-thirds of 

 an inch in length, is darkly coloured with a median lighter band ; 

 the anterior dorsal cirri are long. A. prolifer Mull, is common. 



Myrianida fasciata Milne Edwards, with its foliaceous cirri, 

 occurs off our coasts (see Fig. 149, p. 280). Atlantic, Mediter- 

 ranean. 



FAM. 2. Hesionidae. The body is relatively short, with only 

 a few segments (sixteen to fifty, according to the genus) ; in the 

 larger forms it is cylindrical. The parapodium is usually uni- 

 rarnous ; the dorsal cirri are long and rnultiarticulate ; the chaetae 

 are jointed. The prostomium carries, in addition to four eyes, 

 two or three tentacles, and generally a pair of jointed palps. 

 The peristomium and two or more of the following segments 

 are achaetous, and carry long " peristomial " cirri. The pharynx 

 is very long but unarmed. 



Psamathe Johnston, has many segments ; head with two ten- 

 tacles and a pair of three-jointed palps. P. fusca Jnstn. occurs 

 amongst coralline Algae, to which it bears some resemblance, 

 which is heightened by the moniliform cirri. It is a small worm, 

 less than an inch in length. Mediterranean. Castalia punctata 

 Miill. is dirty green or brownish, with a narrow purplish band on 

 each side. It occurs in deeper water than the preceding. In 

 Ophiodromus the head has three tentacles ; the palps are two- 

 jointed ; there are six pairs of peristomial cirri ; the parapodia 



