may be considered characteristic of its habit ; his figure, though
taken apparently from a rather stunted specimen, is fair, hut the
joints are too long. Lamarck, too, notices the short stem and its
sudden division into sleuder branches, which are its best external
distinguishing characters. In its minute structure it is characterized
by its fine Blattkeule with dentate edges and graceful longitudinal
verruca-spieule. Dry specimens are apt to tu rn white ; perhaps the
white variety mentioned by Lamarck (I. c.) is an instance of this
phenomenon. A variety occurs from Torres Straits with grey cortex,
black verrucæ, white internodes, red joints.
The species figured by De Blainville (Z. c.) differs from ordinary
specimens of AI. textiformis in its yellow soft joints. I t is possibly
a variety of AI. coccinea.
34. Mopsella clavigera.
( P l a t e XXXVII. fig. B ; P l a t e XX XV III. figs. a -a " .)
? Alopsella elongata, Studer, AIB. Ak. Berlin, 1878, p. 606.
Corallum branching strictly in one plane : branches almost invariably
anastomosing in adult at the soft joints, proportionately less,
according to age, in the younger specimens ; the meshes thus formed
are either longicndinally elongated or irregularly polygonal ; the
frond may be either about as broad as it is high, or the height may
he double the breadth. Stem short, moderately developed or weak.
Internodes undulating or seldom straight, compressed, the anteroposterior
diameter having the proportion with regard to the side
diameter of about 3 : 2 ; penetrated towards base by longitudinal
canals. Soft joints distinct, but not large, elongated near base of
main branches, only ju st perceptible in younger parts. Verrucæ
numerous, scattered over sides and back (or front) of corallum, but
leaving a bare space down the middle of its posterior aspect ; tubercular
in shape, slightly prominent. Cortex thin, white and almost
colourless. Axis of internodes rough, white or pale pink (generally
only so in young specimens). Soft joints bright red, pink, or almost
colourless. A*errucæ dirty brownish to white in colour.
Spicules of general cortex :—(i.) Coarsely tuberculated, rather
bluntly pointed, fusiform, of various sizes, the larger ones somewhat
swollen, tapering and sometimes terminated by a small “ Blatt ”
at the other extremity ; average maximum dimensions '17 to ‘21
by -07 millim. (ii.) Blattkeule, compound, with about two lancet-
shaped laminæ, as a rule, and these mainly flattened in one plane,
with a short conical to almost obsolete shaft, covered with smallish
tubercles often deeply dentate ; average maximum dimensions -14
by -07 millim. Spicules of verruca long, slender, curved and pointed,
fusiform, with tubercles fewer and less prominent than those of the
cortical spicules and less numerous near the ends : average maximum
dimensions -25 by -026 to -285 by -044 millim.
Hah. Port Curtis, Queensland, 5-11 fms., bottom sand and shells ;
Port Alolle, 14 fms., bottom rock ; Thursday Island, Torres Straits,
4 -6 fms., bottom rock and sand. Studer’s species was ohtained at
Dirk Hartog Island, AVest Australia.
Ohs. Three young, one older fresh specimen in spirit, one large adult
dry, and one large adult dead aud blackened specimen, and numerous
fresh fragments dry and in spirit represent the species. The largest
specimen, which has lost its terminal twigs, measures 400 millim. iu
height by 275 in maximum breadth.
This well-marked species is very well represented in the collection
by specimens showing differences due to age and other causes,
constituting variations of no inconsiderable extent. The internodes
of none of the branches, except the few primary divisions of the base,
attain a greater lateral diameter than 2 \ millim. or a greater anteroposterior
one than 3¿ millim. ; it is further distinguished by the
constant club-shaped character of the stouter fusiform tuberculate
spicules of the general cortex and by the oblong transverse section of
the internodes.
The tendency to vary in colour is very remarkable ; the axis of the
joints ranges from white to brick-red, th at of the internodes from
white to crimson. The pink colour of the interuode-axes is exhibited
by all the young specimens and lost externally in most of
the adult colonies; but these generally exhibit a trace of their
earlier condition by the pink tin t of the centre of the bard joint, as
may be seen by breaking it across ; on the other band, the colour
may persist in its fullest intensity in the adult, as is shown by a
fragment of a good-sized specimen which occurs with crimson internodes.
The dependence of the amount of anastomosis on the age of
the specimen is another very interesting feature of the species. Of
the two youngest complete specimens (one 40 millim., the other
upwards of 50 millim. long), one has but one case of anastomosis
among its numerous branches, while the other has seven such
cases.
ACABARIA.
Gray, Ann. 8f May. N. II. (4) ii. p. 444.
This genus has the general habit of Alopsella (viz. slender stem
and branches, the latter given off at acute angles), but has fusiform
instead of Blattkeule spicules in the cortex, replacing the small
nodular spicules of Alelitodes.
35. Acaharia japónica.
Alopsella japónica, Verrill, Proc. Ess. Inst. iv. p. 199, vi. p. 80.
? Alelitæa tenella, Dana, U. S. Expl. Exp. Zooph. p. 683.
A fine dry specimen which I cannot distinguish specifically from
the above species ; it measures about 110 millim. in extreme vertical
and 30 millim. in extreme lateral extent.
The terminal branches have the extremely slight thickness of
•5 millim. (excluding verrucæ) ; the colour of the general cortex is
pale scarlet, that of the verrucæ, which are prominent and rounded,
I*' i
1'