PRAXTLLELLA PE^TERMISSA. 327 



author found in an example from Lofoten the tips of the posterior (tenth) bristles 

 feathered with fine lateral fibres, a condition not yet observed here. He also met with 

 one reproducing the terminal segments without bristles. 



In transverse section (Fig. 134) the development of the hypoderm is noteworthy, and 

 between the bristles and hooks a special longitudinal muscular slip is present. The dis- 

 proportion between the dorsal and ventral longitudinal muscles is less than in Nicomache 

 macula ta, but the nerve-cords are similar. A large ovisac occurs in the female on each 

 side. 



The tube consists of mud and sand-grains round a lining of amorphous secretion, and 

 is free. It readily yields to pressure applied externally. Occasionally the translucent 

 secretion projects beyond the external coating of mud and sand. 



Reproduction. — Arwidsson observed, in a large individual from West Greenland in 

 August, the male elements developing, whereas in another from Lofoten in March these 

 elements were minute. 



In a large female from the Gulf of St. Lawrence (35 and 36, 1873) the coelomic 

 cavity is filled with fluid containing many ova — some fairly advanced. 



3. Phaxillella pr2etermissa, Malmgren, 1866. Plate C, fig. 21 — tail; Plate CIX, figs. 



13 — 13 c — bristles and hooks. 



Specific Characters. — The anterior border of the head-plate not produced into a finger- 

 like process. Posteriorly the border is notched. Nuchal organ fairly developed. The 

 papillse of the proboscis kidney-shaped, eight to nine in each row. Nineteen bristled and 

 four unarmed segments posteriorly. The anal cup has a narrow stem coming from the 

 third naked segment ; anal funnel with twenty-two to twenty- three cirri. Segmental 

 organs in bristled segments 6 to 9 (Arwidsson). Bristled segments 1 to 8 have glands 

 anteriorly, large in second, and conspicuous from 5 to 8, where the feet are less. 

 Glands are continued to the posterior end. Reduced hooks in segments 1 to 3. 

 Segments as a rule have bristles. The hooks have gular bristles parted on each side 

 of the main fang, teeth six to seven. Posterior bristles with broad wings; no distal 

 hair-pencil. 



Tube as a rule free. 



Synonyms. 



1865. Praxilla prsetermissa, Malmgren. Nord. Hafs. Annul., p. 191. 



1867. „ „ idem. Annul. Polych., p. 100, Tab. xi, fig. 62. 



1868. Glymene „ Sars. Christ. Vid.-Selsk. Forh., p. 10 (sep. copy). 



1869. Praxilla „ Mcintosh. Trans. Roy. Soc. Edinb., vol. xxv, p. 421. 



1874. „ „ idem. Ann. Nat. Hist., ser. 4, vol. xiv, p. 203. 



1875. „ „ idem. Invert, and Fishes St. Andrews, p. 128. 

 „ „ „ Ehlers. Zeitschr. f. wiss. Zool., Bd. xxv, p. 26. 



1879. „ „ Tauber. Annul. Danica, p. 124. 



Theel. Kongl. svenska Vet.-Akad. Handl., Bd. 16, p. 57. 

 1883. „ „ Wiren. Cheetop. 'Vega' Exped., p. 411. 



