Gatty Marine Laboratory , St. Andrews. 533 



The last of the series is Flabelligera buskii*, with a body 

 about half an inch in length and the outline of a young 

 example of FlabeUigera affinis, both as regards gelatinous 

 investment and the urn-shaped and clavate papillae, but the 

 former have a coarser central axis and the latter are smaller 

 and have thicker stalks. The palpi are pale, whilst the body 

 and branchiae are bright red. The frontal bristles are trans- 

 lucent and delicate, and the articulations wide. The hooks, 

 which are often in pairs, have slender shafts with longer 

 articulations than in F. affinis, and the terminal claw is wider 

 towards the base, is longer, and has a smaller angle with the 

 shaft. 



The Chsetopteridae were introduced to the British Fauna 

 by Dr. Baird in 1854, and thus only occupied a place in the 

 " Addenda " to Dr. Johnston's posthumous ' Catalogue of the 

 non-parasitic Worms in the British Museum/ No addition to 

 the family has been made in the ( Fauna of Plymouth ' (1904), 

 but Mr. Cyril Crossland's f excellent rSsume of the various 

 species of Chcetopterus has done much to clear up the con- 

 fusion in regard to them. Dr. Baird's specimens of Chceto- 

 pterus variopedatus, Ilenier, came from the south coast of 

 England (Cornwall), but it ranges from Shetland to the 

 Channel Islands, and occurs on both the eastern and western 

 coasts as well as the shores of Ireland. Abroad it would 

 seem to be the common form on the western and southern 

 shores of Europe. The remarkable contour, brilliant bluish 

 phosphorescence, and large tube often covered with zoophytes 

 make it one of the most striking annelids. 



The anterior region in the northern specimens of Chceto- 

 pterus variopedatus usually consists of the " head " and nine 

 bristled segments. The so-called " head " forms a broad 

 frill or collar, the great dorsal flaps of which cease at the 

 base of the tentacles, a less conspicuous rim passing on each 

 side to the middle line of the dorsum where fusion occurs. 

 In the preparations of the northern forms, as in life, no 

 anterior frill is present in the mid-dorsal line, and they thus 

 differ from the Neapolitan examples, the dorsal band forming 

 an enlargement and ending bluntly behind the oral rim. 

 In the Neapolitan form the mid-dorsal line has a tendency to 

 differentiation in the shape of a fold or thickening of the 

 rim, and the termination of the mid-dorsal longitudinal band 



* Trans. K. S. Ediu. vol. xxv. p. 420, pi. xv. fig. 13 a, and pi. xvi, 

 fig. 4. 



t Proc. Zool. Soc. 1904, vol. i. p. 270. 



Ann. cL- Mag. N. hist. Ser. 8. Vol. ii. 38 



