PECTINARIA. 37 



discusses the homologies of the cephalic ganglia with the succeeding segmental ganglia 

 of the main cord. 



In his dredging expedition to Finmark, Canon Norman procured numerous Polychaets, 

 which he kindly sent me for identification. They included many of those described in 

 the present volume, such as Amphictenidae, Ampharetidae, Terebellidae, Sabellidae and 

 Serpulidae. The list was published in the ' Annals of Natural History,' 7th ser., vol. xii, 

 p. 283 (1893). It has been deemed sufficient to note them under the head of " Distribution," 

 and the same applies to Kukenthal's Polychaets from Spitzbergen as entered by 

 Marenzeller and E. Mayer in the ' Arch. f. Naturgeschichte ' for 1889, pp. 1 and 132. 



C. Hessle l furnishes a detailed account of the Terebelliformia of Levinsen, with 

 plates and text-figures, and in this the Amphictenidae are included systematically and 

 anatomically. His descriptions and figures are good, and he has illustrated by a series of 

 diagrams the typical nephridia in each family. He treats not only of the European, but 

 of the extreme northern and southern Polar types, those from Japan, the Swedish 

 Expedition to Magellan, and the collections in various museums to which he had access. 



The Amphictenidae are dwellers in sand or fine gravel, though in deep water a few 

 frequent the mud, making their tubes of sponge-spicules artistically and regularly 

 arranged in a transverse manner. They are nocturnal in habit and widely distributed. 

 The northern Gistenides hyperborea, so common in the Gulf of St. Lawrence, Canada, 

 has not yet been met with in British seas. The group has affinities with the Ampharetidae 

 and the Terebellidas, and Levinsen and others form these into Grube's division Terebelli- 

 formia. 



Genus CXXXIV. — Pectinaria, Lamarck, 1812. 



Gistenia, Leach; Amphictene, Savigny. 



Cephalic lobe rounded ; frontal veil (tentacle-membrane of Hessle) cut into triangular 

 fimbriae. 'Tentacles short, covering the cephalic lobe. Two eyes over the ganglia. 

 On the second segment is a cirrus. Buccal segment extending as a nuchal area with its 

 paleae. Body broad in front, tapered posteriorly and of two regions, the anterior much 

 the longer — branchiferous and setigerous ; segments about twenty; posterior region (scapha) 

 of six short segments containing the anus, armed with minute paleae and crenate or 

 " toothed," on each side. Branchiae two pairs, on the third and fourth segments, comb-like 

 in form, with broad teeth (lamellae). A pair of cement glands in the fourth segment. 

 Nephridia in the fourth, seventh and eighth segments, the anterior longer than the 

 posterior. Seventeen pairs of bristle-bundles, beginning on the fifth segment. Bristles 

 capillary with narrow wings. Uncini pectiniform, with several large teeth, and with 

 smaller below. They commence on the eighth segment and continue to the last. Tube 

 composed of neatly arranged and minute fragments of shells, grains of sand, straight 

 or slightly curved. 



i ( 



Zool. Bidrag Uppsala/ Bd, v, 1917. 



