TRAVISIA FORBESII. 



1908. Travisia Forbesli, Moore. Proc. Acad. Nat. Sc. Pliilad., p. 354. 



„ ,, „ Ehlers. Deutsch. Tiefsee-Exped., p. 9. 



1913. „ ,, Augener. Zool. Anzeig., Bd. xli, p. 267. 



27 



Habitat. — First procured by John Goodsir and Edward Forbes, probably in Shetland 

 (G. Johnston). Stomach of flounder, St. Andrews (E. Mcintosh). Dredged in 5 fathoms on 

 a great stretch of sand off Paible, North Uist ; also in Bressay Sound in muddy sand in 

 18 fathoms ; West Voe of Scalloway in muddy sand at 18 fathoms — a region where it 

 occurred in greatest numbers. 



It ranges to Spitsbergen, Greenland, Iceland, and Scandinavia (Malmgren, Fauvel) ; 

 Norway (M. Sars and Canon Norman) ; North Sea, 300 fathoms ; Shores of France 

 (De St. Joseph); Atlantic Coast, U.S.A. (Verrill) ; Northern and Behrings Seas (Wiren); 

 Franz-Joseph-Land (Augener); Cape of Good Hope (Ehlers). 



The body- wall in Travisia (fig. 100) quite differs from that in the ordinary Opheliidse, 



Fig. 100. — Transverse section of the anterior region of Travisia Forbesii, Johnst. mes. Ventral mesentery. 



and conforms rather to that of the Scalibregmidse, for the tough glistening cuticle so 

 characteristic of the former is here an extremely thin superficial layer on the thick 

 hypoderm. A basement-tissue layer and circular muscular fibres lie within, the circular 

 being especially developed in the lateral region, where the fibres of the oblique slope 

 inward to the nerve-cords. These circular fibres remain massive for some distance 

 below, then gradually diminish to a narrow belt in the mid-ventral line. The thickened 

 region is pointed internally in transverse section, the oblique muscle coming from the 

 apex, passing to the upper region of the nerve-cords, and along the side to the ventral 

 edge. The capsule of the cords is intimately fixed to the circular coat on the ventral 

 border. Slender as the oblique muscles are, they mark off a space, as in the Opheliidse, 

 for the ventral longitudinal muscles, which are moderately developed. The segmental 

 organ (so., Fig. 100), which is comparatively large, also occurs in the same area. The dorsal 

 longitudinal muscles form a somewhat thin layer, touching in the mid-dorsal line and 

 extending downward to the origin of the oblique, the lateral and inferior parts of the 

 muscles being thicker than the dorsal. The upper area is occupied by the alimentary-canal 

 with its rugose inner surface, and by a blood-vessel in the mid-dorsal line. The slender 

 oblique muscles have not separated the infero-lateral areas so distinctly as in Ophelia and 

 Scalibregma, but they are clearly indicated. 



