POLYCH^ETA SEDENTARIA OF THE FIRTH OF FORTH. 661 



neuropodium is a short space. On the 3rd setigerous somite there are similar 

 setae, but there is no interval between the notopodium and neuropodium. In 

 the first two setigerous somites the notopodial and neuropodial setae form a 

 single series, and the former only differ from the latter by being slightly thinner 

 and longer, and in colour ; the neuropodial setae are coloured brownish-yellow, 

 the notopodial are colourless. Malmgren states that the pinnulse uncinigerae 

 are absent in the three anterior somites ; but, as we have shown above, their 

 homologues are present. Sars also believed the ventral branch of the feet to 

 be entirely wanting in the first three somites. The neuropodial setae of the 

 branchial region are not uncini, they are simple short bristles cylindrical in 

 shape, and of uniform thickness nearly to the end, terminating in a short trans- 

 parent slender point. The end of the thick part is strongly pigmented, having 

 a brownish-yellow colour. 



The strong curved hook behind the origin of the branchiae is probably a 

 cheeta of the 2nd notopodium specialised. 



The thoracic region consists of 14 somites, each of which is provided 

 with a notopodium and a neuropodium. The notopodium consists of a small 

 fascicle of capillary setae, each having a terminal winged blade (fig. 22 d). The 

 setae are of two lengths, some projecting far from the body, others much 

 shorter, only the blade emerging. The fascicle is borne by a small tubercle 

 flattened antero-posteriorly. The neuropodium consists of a single series of 

 4-toothed uncini, borne on a transverse " torus." 



The abdomen includes the rest of the body, and comprises about 42 somites. 

 This region is distinguished by the entire absence of the notopodial setae, though 

 the notopodial tubercle is recognisable in the first few somites. The uncini, 

 borne on a torus which diminishes in size towards the posterior end, are pre- 

 sent in all the somites. 



Fam. Terebellida 



Subf. Amphitritinae. 



Amphitrite Johnstoni (Malmgren). 



Amphitrite figulus, Daly ell, Powers of the Creator; MTntosh, Fauna of St 



Andrews. 

 Terebella nebulosa, Johnston, Brit. Mus. Cat. 

 Amphitrite Johnstoni, Malmgren, Nordiska Hafs-Annulater, p. 377. 



With regard to Johnston's synonym, it is to be remarked that his descrip- 

 tion applies to the species here in question, but according to Malmgren some 

 of the British Museum specimens catalogued by Johnston as of this species 

 really belong to Thelepus circinnata. 



In this species there are 90 to 100 somites. The prostomium bears a large 



