278 DASYCHONE ARGUS. 
on the edges. A shorter series of bristles occurs at the base, the tips just projecting beyond 
the skin, and these have the same gradation as observed in the longer forms. The posterior 
bristles form a small tuft (Plate CX XIX, figs. 1b and 16’), and are characterised by the great 
elongation of the tips, especially of the more slender forms, the wings in the preparations 
being scarcely visible. One or two bristles at the ventral edge have the wings considerably 
widened at the base, but the tips are attenuate. On examining the anterior tufts of bristles 
with a lens, the sharpest curve formed by the setigerous process is posterior, and the con- 
cavities are dorsal. They are considerably stronger than the succeeding tufts. The ninth 
is less powerful and the dorsal bristles are proportionally longer. In transverse section 
(Plate CX XIX, fig. 1d) they agree generally with the conditions observed in Chone fauvelt. 
The first bristle-tuft has no hooks on its ventral border, but the next seven have long . 
ventral rows slightly diminishing in leneth from before backward, and the hooks occur in 
a single series. The ninth, which begins the posterior series, is dorsal, and is about one-third 
less in breadth than the eighth. Throughout the entire series of rows the hooks maintain 
the same microscopic characters. ‘The anterior hooks (Plate CX XIX, fig. le) are avicular, 
have the posterior outline convex and the anterior concave, the main fang leaves the throat 
at a little less than a right angle, and a series of small teeth occur on the crown above it. 
The anterior outline, whilst concave at the neck, becomes boldly convex at the prow, which 
is smoothly rounded anteriorly and inferiorly, ending in a strap-like basal process, which 
is usually bent a little downward... The hooks diminish in size posteriorly, and the basal 
process is shorter (Plate CX XIX, fig. 1f). The outline, however, is the same. 
The posterior hooks of Dasychone lucullana from Naples have the same general outline 
as in D. argus, but as the specimens are much smaller than the British the teeth on the crown 
are less distinct; eight or nine teeth occur in lateral view from the crown on the slope to the 
main fane—leaving about half the edge smooth. ‘The forward bulge of the prow is marked, 
and the posterior outline is strongly convex—with a broad but short basal process. The. 
curved striz a little behind the prow pass into the basal process. In the larger D. argus, 
the teeth above the great fang are ten or eleven; the crown goes further, backward, so that 
the posterior curve is less convex. The posterior basal process is similar, but often smaller 
than in the other form, and the strize behind the prow are bolder. One or two oblique strize 
also appear in some on the neck. Other specimens, however, as in that figured, agree in 
the posterior curve with the Neapolitan form, so that they seem to be varieties of the same 
species. 
Habits—In confinement it readily expands its branchial fan, and is less shy than many 
others. Moreover, a fresh and transparent tube is rapidly secreted if the annelid be left 
under favourable circumstances. 
Reproduction —Dalyell (1853) had specimens which spawned in May, June, August and 
September, the white ova being immersed in the thinnest gelatinous matter. He found 
that, after the loss of the branchial plumes, in fifteen days, the “ rudiments of a regenerating 
plume rose, as several shoots one-eighth of an inch long, and in others three specks on the 
back of the ribs were visible. Incipient fringes began to clothe the latter, and in twenty-three 
days from the date of mutilation the branchiz had attained a third of the dimensions of those 
they were replacing.” In another example the plume “ proved a fine reproduction ”’ in two 
months; whilst in a third, viz., a portion of the posterior end of the body, 116 days elapsed 
