THELEPUS PERICENSIS. 437 



Thelepus Leuckart. 



Archiv naturg., 1849, 15, p. 169; St. Joseph, Ann. sci. nat., 1894, scr. 5, 17, p. 183. 



Lumara Stimpson, Invertb. Grand Manan, 1853, p. 30. 



Venusda Johnston, Cat. Annelids Brit, mus., 1865, p. 241. 



Neoltis Malmgren, Ofvers. K. vet. akad. Fi rh., 1865, p. 388. 



Phenacia Quatrefagbs, Hist. nat. annelcs, 1865, 2 p. 374. 



Heterophenacia Quatrefages, Ibid., 1865, 2, p. 389. 



Thelepodopsis Sars, Forh. Vidcnsk. selsk. Christiania, 1872, 1871, p. 415. 



Thelepus pekicensis, sp. nov. 

 Plate 80, fig. 4-6. 



Yellow, of a weak brownish cast. The branchiae and tentacles brighter 

 yellow. 



Body anteriorly broad, very conspicuously narrowed and tapering caudad, 

 strongly narrowed from the fifteenth somite cephalad and also narrowing from 

 the same region caudad to the twentieth somite, there of nearly uniform width 

 to about the twenty fifth, from where it again strongly narrows to the much 

 more slender posterior division of the body, the caudal end of which is strongly 

 tapered, with the tip pointed. The anus is a smooth, funnel-shaped, opening, 

 with the sides weakly grooved, but without processes. The number of somites 

 in the type is one hundred and ninety-five, or about that number. The greatest 

 width of thorax, 7 mm. ; the width caudad of the thirtieth somite, from 3.3 to 

 3.5 mm. The length difficult to determine because of the coiling of the body, 

 but not far from 155 mm. 



The prostomium presents a dorsal flap of moderate size, which is transversely 

 wrinkled, as is common. On each side there is a conspicuous band of eyes. 

 The tentacles long and slender, grooved, the grooves not strong. 



The branchial filaments form three continuous transverse rows without 

 any distinct clear space in the middorsal region. The filaments are slender, 

 decidedly more so than the tentacles, and are strongly curled in a spu-al. They 

 are numerous and closely aggregated, and extend down on each side to, or in 

 the case of the first series, below, the level of the lower edge of the notopodial 

 processes. 



Segmental papillae are present under the setigerous processes on the second 

 to fifth setigerous somites. 



The setae begin on the third somite, and are found on all the succeeding 

 somites excepting at the caudal end. The setae are short and acutely pointed. 



