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somewliat too wide a scope, it is at the same time true th a t a resting
place or jdaces must be found for those numerous and varied species
which are intermediate between the more plainly marked genera
Desmacidon, Esperia, and AlyxiUa. For some of these forms older
genera may be employed, e.g. Dirrhopalum{Flocamia) for + . coriaceus
and microcionides (as 1 have endeavoured to show in a paper “ On
the Genus Flocamia &c.,” Journ. Linn. Soc., Zool. xv. pp. 481, 482).
Lor some such species (abyssi, pldyctenoides) Mr. Carter employs
the old term Halichondria ; but the typo of Fleming's genus Halichondria
is Spongia papillai'is, Pallas, which appears to be a
synonym of Halichondria {Amorphina, Schmidt) panicea, viz. a
llenierid and not a Desmacidine, and so the genus Halichondria, if
maintained, should be restricted to Ronierida?.
Amphilectus, it seems to me, may he kept with advantage for
forms with dentate or navicular equianchorate flesh-spicules, with
smooth skeleton-spicules and absence of any echinating spicules : the
type of the genus is Isodictya gracilis of Bowerbank. I t may be
perhaps necessary to admit forms in which the tibiella (when present)
is slightly spined, as in Desmacidon anceps, Schmidt. Vosmaer’s
limitation of Desmacidon to species with horuy fibre is not justified
by the species he has assigned to it.
63. Amphilectus tibiellifer. ( P l a t e XL II. figs. t - t " .)
Erect, massive, sessile by broad base ; sponge broader tiian high
and higher than it is thick, decreasing in thickness towards upper
margin, which presents a narrow edge. Sponge-mass honeycombed
by a system of tortuous, anastomosing spaces, 3 millim. and upwards
in diameter, separated in most cases merely by trabeeulæ of substance.
Surface perforated by the closelj-set openings of the above-
mentioned spaces ; surface of sponge and of the trabeeulæ between
openings even, slightly villous in spirit. Texture of sponge in
spirit firm, subelastic, tough ; colour dark reddish umber-hrown.
Sarcode pale reddish brown, rather soft. Main skeleton consisting
of compact spiculo-fibre formed of spicule no. I , showing no
horny uniting substance, about 3 to 6 spicules broad, irregular ;
some only of the primary fibres go straight to surface, the secondary
fibres usually meet the primaries at acute angles ; primaries
about '5 millim. apart. Dermal skeleton consisting of a network
of spiculo-fibre 2 to 4 spicules broad, the spicules mostly loosely
aggregated ; meshes of network about Bo millim. apart.
Spicules :—(1) Skeleton acuate, strong, smooth, straight or slightly
curved ; base rather squarely rounded, shaft cylindrical, tapering
to point from about three diameters from end; size -38 by 'Old
millim. (2) Tibiella, slender, almost straight ; shaft smooth, of
same diameter throughout, passing graduaUy into an oval smooth
head about half as thick again as shaft; size '25 by -0042 millim.
(thickness of head) ; abundant in dermal membrane and interior.
(3) Equianchorate, navicular or shuttle-shaped, with palms rather
longer than /ro a d , inner margins truncate, as seen from front,
tubercle distinct; shaft slightly and gradually curved; size -016
millim. long : abundant, especially in dermal membrane. (4) Tri-
curvate smooth, strong, the curves bold, the points sharp ; size -15
by -006 millim.
Heih. Prince of Wales Channel, Torres Straits, 7 fms. ; bottom
sand. ’
A specim/n and a fragment in spirit, the former 80 millim.
broad by , o high by 40 thick at present base ; it is almost semi-
mrcular in outline, the round margin uppermost ; it appears to have
been torn from a rather larger specimen.
ii'^?r ^ tifiieUa with smooth ends distinguishes it from
all allmd species oi Desmacidon (Schmidt) but D. emphysema, Schmidt
(JB Comm. Unters. deutsch. Meer. ii.-iii. p. 118), and D. physa (id.
I. c.), the latter of which, however, has the surface of the spoime
even and tim sponge itself flask-shaped ; in the former the sponge is
covered with biibble-like elevations. Desmacidon arciferum, Schmidt
which has a similar tibiella, appears to be an OpUitisponqia, from
the strong horny fibre and the echinating arrangement of some of
its acuates. D. diance, id., has, besides, tho tridentate anchorates of
MyxlUa and a strongly horny fibre ; and both it and D. anceps,
id., possess the forcipiform spicules, which occur in Ilcdichonclria
forcipis, Bk.
64. Amphilectus hispidulus.
( P l a t e XL. fig. C ; P l a t e XLI. figs. y - y " .)
Erect, clathrous ; formed of a number of irregularly branching
and anastemosing masses, their surface more or less covered with
low cylindrical or ridge-like elevations. Vents? Surface hispid with
closely set hair-like terminations of the primary skeleton-fibres.
le x tu re of sponge in dry state firm, elastic, but readily torn, in
spirit soft c k s tic ; colour dull pale brown in dry state, in spirit
pale pinkish brown. ^
Main skeleton of the type known as “ isodictyal,” viz. consisting
of primary lines running straight to the surface, at right angles to
it, connected by numerous transverse secondary lines set at right
angles to the pnmaries; distance between primaries at surface
about -25 millim., between secondaries -17 millim., length of the
snriace processes of primaries about -3 millim. Fibres formed of
pale yellow horny material, cored by the axial spicules (no 1) to
the extent of about ono third of their total thickness in the case of
the secondary fibres, about three quarters in the primaries; margins
of horny material clearly seen outside the spicules, except in the
surlace-tufts of the primaries, which are opaque and dark-coloured •
spicules in series of 3 or 4 in the primary, of 2 in the secondary
fibres, of about 6 in the dermal tufts of the primaries. Dermal
skeleton consisting of an irregular reticulation with polygonal
meshes made up of fibres, some of which resemble the primmdes
!; :
ite'