492 
THE VOYAGE OF H.M.S. CHALLENGEK. 
The size of this species affords a favourable opportunity for the examination of the 
minute structure of the body-wall. In the preparations the cuticle has disappeared, but 
the basement-tissue of the hypoderm is massive, especially laterally and interiorly. The 
pigment distinguishes the hypoderm, while the deeper parts show the pale cells and 
glands. The circular muscular coat has a much greater tendency to stretch downward 
into the basement-tissue than in Sabella pavonitia. Somewhat within the outer third of 
each longitudinal ventral muscle the outer fibres of the circular coat begin to spread 
themselves over the basement-layer, and on reaching the nerve-area it is found that the 
whole coat forms a series of fibres imbedded in this tissue, almost to the pigment. These 
bundles of fibres join each other so as to form a complex mesh work. Consequently 
the nerve-area has only areolated basement-tissue outside the cords, the large lateral 
branches of which are readily distinguished in this translucent matrix. The large neural 
canals are filled with a coagulable yellowish fluid. The longitudinal muscular fibres on 
each side of the cords and also at the base of the alimentary ligament enclosing the 
blood-vessel are well seen. The longitudinal dorsal muscles are massive, and the 
symjahysis in the median line is deep and close. The suspensory ligament of the 
digestive canal arises only from the fibro-muscular bands below the latter. 
The Sabella fusca, Ehrenberg (Grube), in the British Museum, from Ceylon, seems 
to approach this form closely, both in the colour, external appearance, and hooks. The 
tube is a tough chitiuous one, with sand and mud externally and the egg-cases of a 
Mollusk (like those of Murex). It probably came from the tidal region. The absence of 
definite figures of the hooks renders diagnosis difficult. This species may be connected 
with the Spirographis australiensis, Haswell, as described in his recent paper on the 
Australian Sabellidee and Serpulidse.^ 
Laonome, Malmgren. 
Laonome haeckelii, n. sp. (PI. XXXa. figs. 7-9). 
Habitat. — Dredged off St. Vincent, Cape Verde Islands. 
A fragment of the tail, measuring about 11 mm. in length, with a transverse diameter 
at the anterior end of 2 mm. 
All that can be said of the external characters is that the dorsal surface is rounded 
and the ventral flattened. The latter surface, moreover, is marked by a broad, dark 
brownish central band, which occupies the region of the scutes. At the tip of the tail 
ventrally are two brown pigment-specks. 
1 Journ. Linn. Soc. New South Wales, vol. ix. (sep. copy), p. 24. In this paper the draftsman seems to have inverted 
some of the figures. 
