170 TRYPANOSYLLIS ZEBRA. 



more distinctly so posteriorly, where it ends in two caudal cirri with numerous articulations. 

 The dorsum is somewhat rounded anteriorly, the ventral surface flattened. Anteriorly 

 the dorsum is beautifully banded with madder-brown or violet-brown bars— two in each 

 segment, the longer touching the bases of the opposite cirri, which are pale, and the 

 shorter following closely behind. Both bands can be traced to the posterior third, 

 becoming considerably paler, however, behind the middle, the shorter bar then disappearing, 

 and by-ancl-by the longer also fades, leaving the tip of the tail pale yellowish— from the 

 intestine. The ventral surface is dull yellow. Dorsal cirri characteristically large, and all 

 are distinctly articulated and alternately long and short, the latter having about twenty 

 articulations, the former about double the number. They are occasionally coloured violet 

 by the corpuscles (De St. Joseph). Setigerous region blunt and bilobed with two flat, 

 conical papillas below the spines. Bristles translucent, with traces of serrations on the 

 convex margin of the distal end of the shaft ; terminal pieces rather shorter and broader 

 than in Pionosyllis, boldly bifid at the tip and spinous on the edge. Ventral cirrus ovato- 

 lanceolate ; extends a little beyond the setigerous region. 



Synonyms. 



1860. Syllis zebra, Grrube. Arch. f. JSTaturges., Bd. xxvi, p. 86, Taf. iii, f. 7. 



1861. „ „ idem. Ausflug Triest, p. 143, Taf. iii, f. 7. 



1864. Trypan osyllis Krolmii, Claparede. GUanures, p. 38, pi. vii, f. 2. 



1865. Syllis zebra, De Quatrefages. Annel., II, p. 28. 



1874. „ „ Marenzeller. Sitzb. k. Akad. Wiss. Wien, Bd. lxix, p. 40, Taf. v, f . I. 



1875. „ KroJinii, Marion and Bobretzky. Ann. Sc. Nat., 6 e ser., torn, ii, p. 35. 

 1879. „ zebra, Langerlians. Zeitsch. f. w. Zool., Bd. xxxii, p. 556, Taf. xxxii, f. 17. 



1885. „ „ Oarus. Fauna Medit., II, p. 230. 



1886. ,, Krohnii, De St. Joseph. Ann. Sc. Nat., 7 e ser., torn, i, p. 180, pi. ix, f. 51—56. 

 1904. „ „ Allen. Journ. Mar. Biol. Assoc, n.s., vol. vii, p. 220. 



Habitat— Between tide-marks, Herm, 1868. Common in dredgings from Millbay 

 Channel and Asia shore, as well as from Yealm, Plymouth (Dr. Allen). 



Cherso (Grube). Port Vendres (Claparede). Bay of Muggia in the Adriatic 

 (Marenzeller) . Marseilles (Marion and Bobretzky) . Madeira (Langerhans) . Common in 

 dredgings 10—15 metres, at St. Dinard, France (De St. Joseph). 



Head (Plate L, fig. 9) rounded trapezoidal, slightly narrower posteriorly where a 

 forward incurvation at the median depression occurs. Eyes four, black, rounded or ovoid, 

 rather large, placed anteriorly, the posterior pair slightly the smaller. Median tentacle 

 arising between the anterior eyes, broad at the base and tapering distally, with about 

 thirty articulations. Lateral tentacles somewhat shorter. Palpi of average size. Upper 

 of the first pair of tentacular cirri very long (forty articulations). 



Body comparatively long (50 to 76 mm.), large, rounded dorsally and flattened 

 ventrally ; segments 190 ; slightly tapered anteriorly, more distinctly so posteriorly where 

 it ends in two caudal cirri with numerous articulations (Plate L, fig. 10). The dorsal 

 cirri are large, and alternately long and short, the former having about forty articulations, 

 the latter about half the number. 



In front it is ornamented by violet transverse bands which occur on each side of the 



