and the shorter and more slender bristles externally. Ventrally are three bristles having
above the fang respectively two, one, two spines.
The thirteenth foot has dorsally scales and spines. Ventrally three bristles, the
hooks above the fang being respectively one, two, one.
The fifteenth has scales and spines. Ventrally the two bristles have one spike
each above fang.
The twentieth foot (cirrus-bearing) has longer and more tapered dorsal bristles, the
granules on which are less distinct, especially in the tapered forms. The shorter, broader
forms show the granules distinctly. Ventrally the three powerful bristles have only the
great fang. A typical foot is shown in Plate XXXVI, fig. 13.
The terminal feet have dorsally the granular bristles more pointed and less curved
than in front, moreover the tips are smooth ; while ventrally the tips are more elongated,
and have numerous spines above the great fang. One of the smaller forms is X 90 in Plate
XXXVII, fig. 8. The ventral bristles of this form are much stouter than in Lætmatonice
filicomis.
This species is specially subject to the attacks of Loxosoma, which occurs abundantly
on the ventral surface and cirri, on the feet,, mouth, and other parts. Parasitic algæ
often grow on the bristles and spines, with mud, sponge-spicules, and other débris
entangled. A remarkable hydroid creeping along the bristles is also present. Hydroids
and Polyzoa, indeed, are not uncommon.
In habit this species appears to correspond with Aphrodita and Lætmatonice.
Reproduction.—The ova were well advanced in July in those-from Herm and other
parts of the Channel Islands. Lo Bianco found the Neapolitan examples with developing
ova in October, and increasing in size in November.
An interesting account of the development is given by Hr. R. von Drasche,1 of
Vienna, from observations made at the rich Marine Station of Trieste. He found the
ripe forms in October and November, the latter month being probably that in which
deposition of the eggs generally takes place. The egg measures 0*2 mm., and he watched
it through all the stages of segmentation till the embryo moved within the capsule by aid
of cilia. I t then issued as a pear-shaped trochosphere, with an equatorial circlet of cilia
and a tuft in front ; while a solid mass of deutoplasm occurred in the middle of the body.
The violet-colôurèd larva soon acquires another ring of shorter cilia behind the first or
pre-oral, an anal ring of cilia appears, and it swims about actively. Two red eyes are
developed in front. The anterior end becomes triangular, and a characteristic broad
cellular collar lies behind the eyes—the mouth, with a tuft of cilia, opening towards (in
front of) its posterior border ventrally. On the fourth day the larva has increased in
size, and the yolk-mass has concentrated into a covering for the alimentary canal. On the
under surface of the snout are five small papillæ—organs, however, not homologous with
the cephalic processes of the adult. There are now three segments with bristles. On
the sixth day it is still larger. The alimentary canal is complete. The equatorial belt is
smaller. There are five segments. The feet show a large yellow spine and bristles, the
latter having a structure conformable to the adult type, though the glochidiate forms
1 £ Beitr. z. Entwickèlnng d. Polychaeten/ pp. 7—11, Taf. ii, f. 8—20; and Taf. iii, f. 1—4,
1885.
are not yet present. Besides the structures mentioned, the young Hermione has now
three pairs of eyes, and a process (first foot) behind the collar.
Savigny (1820) first distinguished, the species, though his description is by no
means diagnostic.
Delle Ohiaje (1823) refers to the condition of the alimentary system in speaking
of the anatomy of Pleurophyllidia, and gives a figure of a moribund example in his
‘ Memorie.’ He thought the papillæ of the proboscis were taste-organs. He shows the
globules of the blood. In his * Descrizione ’ he mentions its common occurrence at
Naples, and reproduces the plate from the ‘ Memorie.’
The Aphrodita hystrix mentioned by Oersted1 probably refers to Lætmatonice.
Kinberg (1858) followed De Quatrefages in making two species, viz. H. hystrix and
H. hystricella; but so far as can be ascertained this distinction rests upon variation, and
Claparède was of the same opinion.
De Quatrefages. (Annelés) saw in a male Hermione hystrix the spermatozoa issue in
the form of a white thread at the base of the inferior branch of the foot of the nineteenth
segment. They probably escaped from the segmental papilla between the feet. This
author distinguishes between his H. fallax and this species by the fact that the median
antenna in H. hystrix is least, and that the bristles of the scale-bearing feet have the
points unarmed, while those of the inferior feet are tridentate (instead of the tips
straight and the inferior bristles bidentate as in H. fallax). The bristles of the ventral
division have curved apices, whereas in H. hystricella from the Mediterranean, &c., these
are straight, and Kinberg says so also.
Claparède2 has already pointed out that De Quatrefages was wrong in thinking that
absolute reliance was to be placed on the number of the denticles at the tip of the spines
or of the ventral bristles, and he also showed the condition generally of the anterior feet
in contrast with the posterior. He enters into the uses of the guard for the tips of the
long dorsal spines, and demonstrates that a process also appears in the developing ventral
bristles before they pierce the surface. He alludes to the granular bristles, which
had previously been described by Johnston and Kinberg, and points out the nature of
their tips, with the swollen part beneath the point, as shown in one of the present figures.
He mentions having found in a single example a long, simple bristle in the ventral division
of the foot, probably a pathological phenomenon. He speaks of the warts on the
surface, already mentioned by Pallas, Johnston, and KöHiker. He likewise, alludes to
the structure of the peritoneum, and that of the dorsal cirri.
Grube (1874) says De Quatrefages relegated Hermione hystrix to the Mediterranean
and H. fallax to the Atlantic.
Prof. Jourdain,s in his account of the histology of the integument and sensitive
appendages of this species, describes the irregular polygons formed by the cells of the
epithelial coat, the nerves which ramify in it, and the thinly distributed nerve-cells. On
the ventral surface, the warts, of which Claparède had formerly given a figure, have a
central pore, through which communication with the granular layer of the epidermis
1 c Annulât. Danic. Consp./ p. 11, 1843.
2 ‘ Ann. d. Golfe d. Nap./ p. 50, 1868.
3 ‘ Archives Zool. Expériment.5 (2), vol. v, p. 91 (1887), pis. iii and iv.