494 HETEROCLYMENE ROBUSTA. 
and there are over 100 segments. The digestive and the perivisceral systems agree with 
Capitella. The anterior segments are short and broad, the posterior long and narrow. The 
anterior bristles are winged, the posterior region has the characteristic hooks dorsally and 
ventrally. 
SYNONYMS. 
1857. Capitella fimbriata, van Beneden, p. 139, Bull. ’ Acad. Roy. Belg. 
1859. S iy D’Udekem. Mém. Acad. Roy. Belg., t. 31, p. 26. 
1864. » _ filiformis, Claparede. Glanures Zoot., p. 49, pl. iv, fig. 10. 
1865. Aucistria minima, De Quatrefages. Annelés, ii, p. 252, pl. xi, figs. 283—34. 
1868. Capitella filiformis, Claparéde. Annél. Neap., p. 273. 
ie castanea, idem. Ibid., p. 275, pl. xxvii, fig. 2. 
1873. Aucistria capillaris, Verrill. Americ. Assoc. Proc., xxii (Explor. Casco Bay), p. 385. 
1874, Arenia, sp. (= Notomastus capillaris, Verrill). Amer. Journ. Sc., vol. vii, p. 39, and p. 385 
as above. 
1881. » idem. New Engl. Annel., p. 305. 
1887. Capitella fimbriata, Hisig. Capitell., p. 839, Taf. i, fig. 4; Taf. xxvii, figs. 16—19; Taf. xxxii, 
mes W733 Way, sos, me, B73 Whi, sooxinl, ihes, 7S 3 
Taf. xxxiv, fig. 37; Taf. xxxviii, fig. 9. 
1915. Aucistria mimma, Allen. Journ. M. B. A., vol. x, p. 638. 
1922. Heteromastus filiformis, McIntosh. Ann, Nat. Hist., ser. 9, vol. ix, p. 25. 
Habitat.—In sand west of Salthouse Lake, Plymouth (Allen). 
Distribution.—Rochelle (De Quatrefages) ; Mediterranean (Hisig); United States of 
America (Verrill). 
Famity MALDANIDZ. 
HETEROCLYMENE ROBUSTA, Arwidsson. 
Two examples come from Plymouth, and I have to thank Dr. Allen for the opportunity 
of examining them. Besides the lateral notches in the cephalic border, the rim behind has 
crenations, the median deepest posteriorly. The segments in the middle of the body can 
be much elongated, one bemg about an inch and three-quarters. The bristles and rows of 
hooks project outward on enlargements at the segment-junctions. The anal disc is an 
exquisite structure, as finely radiate as the operculum of Serpula vermicularis, only the 
anus is in the centre of a cone, over which the radii pass downward and then upward to the 
minutely crenate edge. The mid-ventral cirrus is somewhat flattened as well as longest, 
and there are three or four shorter cirri on each side, rather irregularly arranged, a 
portion of the dorsal edge being bare. . 
The tube is as thick as that of Lanice conchilega, but firmer, retaining its cylindrical 
form until somewhat severe pressure is applied. It is composed of shell-fragments, minute 
shells, spines of Echinoderms, smoothly filled in with fine grains of sand and secretion. 
