280 DASYCHONE ARGUS. 
when eight or nine segments are present, the eyes disappear, and the branchial filaments 
have a tendency to bifurcation, but are yet devoid of eye-specks. 
In a young example procured at the Hast Rocks, St. Andrews, in May, 1867 (R. M.), 
and measuring in all about 4 mm., there are twenty-nine bristled segments; the dorsal 
processes of the branchiz are proportionally large and slightly clavate in outline. Four 
pairs occurred on each filament. ‘The collar is well formed. The vent has two prominent 
papillee. 
De St. Joseph (1894) found a young form of 5 mm., viz., 3 for the body and 2 for 
the branchie. Five pairs of branchize were present, each with five pairs of eyes ; six anterior 
and twenty-four posterior segments. 
The tube is composed of tough secretion, often of a brownish hue and more or less 
coated with mud. On shell-ground in 10 fathoms, off St. Peter Port, Guernsey, the tubes were 
surrounded by fragments of shells and a young Arca may be included. The same occurred 
in a small specimen found under a stone between tide-marks at Herm, and under similar 
circumstances at Lamlash, Arran. Algze also occasionally grow on the tubes and the structures 
attached. Off Bantry Bay the tubes were of tough secretion coated with greyish mud, and 
comparatively long. Dalyell observed that the fresh secretion is as clear as crystal, but 
becomes opaque subsequently. It can form several tubes in succession. De St. Joseph 
(1894) notes that, when detached from the site to which it is adherent, it rapidly pours 
out secretion and attaches neighbouring objects. The tube is horizontal in position. 
The Sabella lucullana of Delle Chiaje' and subsequent authors seems to be a very closely 
allied form, the descriptions so far being insufficient for discrimination from the British 
species. Its tube is similar. An anterior bristle, with broader wings, is shown in Plate 
CXXIX, fig. 2; a curved form in Plate CX XIX, fig. 2a, and a hook in the same plate, fig. 2b, 
and another from a specimen sent from the Naples Zoological Station in Plate XXVIII, fig. 6. 
All agree with the typical form. 
Claparéde (1868), in Dasychone lucullana, found that the lateral branches of the vascular 
rete enveloping the imtestine had a series of contractile blind appendages, as in Protula Dysterv, 
Huxley. Some of these are simple and others ramified. 
Roule? (1884-5) gives an account of the development of Dasychone lucullana, D. Ch., 
the eggs of which he found early in April immersed in a voluminous mass of mucus. By 
the 20th of May the larva had only two segments. 
De St. Joseph (1894) describes the eyes of this form as composed of twenty to 
thirty rods, terminating in crystalline cones, surrounded by pigment, and he thinks the 
appendages of the branchial filaments protect them when in the tube. 
There is nothing in Hornell’s Dasychone Herdmani (1891) to distinguish it from the 
present species. 
Bernardi (1911) considers that this form may be D. lucullana, D. Ch., for both Grube 
and Kélliker have found D. bombyx in the Mediterranean, and the distinctions in regard to 
segments, the appendages of the branchial filaments and the longer palpi are not material. 
The same view is held by the author. . 
Fauvel (1914) observes that the branchize of Dasychone infarcta, Kroyer, from St. Vaast- 
1 <«Memorie,’ p. 218, tav. xl, fig. 23; * Descrizione,’ p. 72, tav. xcvi, fig. 23. 
2 “Revue Se. Nat. Montpellier,’ 3° sér., t. iv, p. 463. 
