276 NOTOMASTTTS LATERICEUS. 



segment is sterile. Reproductive aperture generally on the last anterior or in the first 

 posterior segment. 



1. Notomastus latericeus, Sars, 1851. Plate XCII, fig. 2— part of body ; Plate XCVIII, 

 fig. 19 — anterior region ; Plate CVII, figs. 9 — 9 b— bristle and hook. 



Specific Characters— Read conico-acuminate, of two rings; at its base are two 

 groups of brownish grains marking the nuchal organs. Body 6 to 8 in. long, more or 

 less rounded dorsally, flattened ventrally, a little tapered in front of the large anterior 

 region, then gradually diminishing to a tail with a slightly upturned vent and two 

 papilla3 beneath. Behind the larger anterior region of the buccal and eleven bristled 

 segments the ventral surface is marked by a central band with a line at each side, but 

 posteriorly this becomes less distinct, being merged in the ventral groove of that region. 

 Anterior segments two-ringed and tessellated on the surface, whilst the posterior region has 

 larger segments with prominent tori for the hooks. Bach segment anteriorly has a double 

 median dorsal elevation and two long lateral ridges which pass to the ventral surface. 

 Posteriorly the four tori are more nearly equal and more widely separated, two being 

 dorsal and two ventro-lateral. The median dorsal elevations have disappeared. 



Colour of the anterior region deep reddish, behind which it is reddish-brown, and 

 then greyish posteriorly. Sometimes blotched with pale lateral areas (yellowish- red, 

 Grube, Cams), and with large white bodies in the coelom. Anterior bristles with simple 

 straight shafts, acute tips, and narrow wings. Hooks appear at the twelfth bristled 

 segment on a double process in the mid-dorsal line, and they continue to the twentieth 

 segment of the region. Thereafter both processes diminish, so that at the thirtieth no 

 trace exists, only a dorsal and a ventral torus being present. The hooks are minute 

 with an elongated shaft, a main fang above the slightly narrowed neck, and two spikes 

 above it. Pore with palpocils, between the dorsal and ventral bristles of the first 

 region ; in the second region it occurs between the dorsal and ventral tori. On each 

 side, a little behind the double median torus, in segments six to eleven, is situated the 

 genital papilla. 



Synonyms. 

 1851. Notomastus latericeus, Sars. Nyt Mag. f. Naturvid., Bd. vi, p. 199. 

 1853. „ „ idem. Ibid., Bd. vii, p. 381. 



1856. „ „ idem. Fauna Lit. Norveg., ii, p. 9, Tab. 2, figs. 8 — 17. 



1861. „ „ Danielssen. Reise, 1857, Nyt Mag. f. Naturvid., xi, p. 54. 



1862. ?Capitella rubicunda, Keferstein. Zeitschr. f. wiss. Zool., Bd. xii, p. 123, p]. xi, figs. 7 — 18. 



1863. „ „ Claparede. Beobach. ii. Anat., p. 26, pi. xv, figs. 1 — 14. 



1864. Notomastus latericeus, Grube. Insel Lussin, p. 86. 



1865. Arenia cruenta, De Quatrefages. Annel., t. ii, p. 250, pi. xi, figs. 16 — 23. 

 ,, Notomastus latericeus, idem. Ibid., Id., p. 258. 



1867. Waudanis rubicundus, Kinberg. Ofvers. Vet.-Akad. Forh., Aar xxiii, 1866, p. 343. 



„ Notomastus latericeus, Malmgren. Annul Polych., p. 97. 



1869. ?Capitella rubicunda, Grube. Mitt. St. Vaast, Abh. Sehles. Ges., 1868-69, p. 37. 



1873. Notomastus latericeus, Sars. Bidrag Christ. Fauna, p. 74. 



„ „ „ idem. Nyt Mag. f. Naturvid., Bd. xix, p. 274. 



1875. „ „ Ehlers. Zeitschr. f . wiss. Zool., Bd. xxv, pp. 25 and 62. 



