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before me gradations in respect to length and breadth. Both are
slig h t^ narrower in front than behind, sculptured with line concentric
striæ and more or loss indistinct shallow radiating markings,
a feature unnoticed by Deshayes. Although tho dentition is
described by th at author as somewhat different, I am hound to say,
after a most careful examination, th at both the number and position
of the teeth arc absolutely similar. In the left valve I find three
teeth, the anterior one being very small at the termination of the
inner margin of the hinge-plate, which is grooved on both sides of
tho beak. The central tooth is large, prominent, situated immediately
beneath the point of the nmbo, and the third is insignificant
and posterior to the narrow oblique ligament. The right valve has
a large prominent tooth a little in front of the apex of tho umbo,
and generally the extremity of the inner edge of the grooved hinge-
plate is raised into a tooth-like prominence behind the ligament,
which extends not only within the valves, hut also along the hinge-
line just above the teeth. The single specimen from Port Molle and
one in the Cumingian collection are peculiar in having two or three
of the shallow radiating impressions towards the hinder ventral extremity
deeper, thus producing a wavy margin to the valves at that
particular spot.
47. Scintilla aurantiaca. ( P l a t e Y II. figs. H, H 1.)
Deshayes, Proc. Zool. Soc. 1855, p. 179; Soiverhy, Thes. Conch, vol. iii.
p. 176, pi. 234. fig. 5.
Hah. North Australia, under stones at low water {Jukes); island
of Nairai, Fiji, at low water {Brit. AIus.) ; Port MoUe, Queensland
( Coppinger).
The specimens from Port Molle agree precisely with the types of
8. aurantiaca in the national museum. There are some other species
which I cannot distinguish from i t ; these are S .fa b a , Desh., 8.
Forbesii, Desh., S. palliclula, Desh., 8. amhigua, Desh., 8. horneensis,
Desh., and 8. adamsi, Desh. The last and 8. faba are placed by
Sowerby in the group of “ species with no hiatus ” in the ventral
margin. This location is incorrect, for both gape slightly, and in
fact Deshayes, in his description of the latter, says “ margine inferiore
angustissme hiante.” This opening appears to be subject to
variation in shells which are unquestionably the same specifically;
and therefore I believe it probable th at all the above-mentioned
so-called species will prove to he variations of Lamarck’s Psammobia
aurantia, which, according to Sowerby’s figure (Conch. Icon,
fig. 20, S. mauritiana), has an extremely wide gape beneath. The
latter species is said to be synonymous with 8. aurantia by Deshayes
(Anim. sans A ert. vol. vi. p. 180, Galeomma aurantia), and von
Martens expresses a similar opinion (Möbius, ‘ Meeresfauna Mauritius
&c.,’ p. 322). Deshayes (P. Z. S. 1855, p. 167) says that the Lamarckian
shell is a Galeomma.
Tho animal of Dr. Coppinger’s shells agrees with the description
given by Quoy and G-aimard of their Psammohia vitrea and with the
figure in Mobius’s work above referred to, pi. xxi. figs. 10 a, b. The
foot protrudes a t the narrower end of the shell; it is small when
retracted, of a boot-like form, roundly carinate at the base, pointed
at the tip, and furnished with what is probably a byssiferous process
at tho posterior end (“ talon,” Q. & G .); this is of an opaque white
colour. The mantle is open in front and the anterior half of the
ventral margin for the passage of the foot, and united along the
rest of the basal and hinder margins, where there is a minute
siphonal perforation. The surface of the mantle beneath is covered
with papilla?, and the membranous marginal expansion in life probably
covers nearly the entire surface of the shell, for even in spirit
specimens it still extends halfway up the valves. There are two
labial palpi on each side. From this description the close relationship
with Galeomma is very apparent.
The dentition of this species, according to my observation, does
not agree with the description given by Deshayes. In the right
valve I find a prominent tooth a little in front of tho beak, and a
second more remote hehiud i t ; the left valve has two teeth, of
which the anterior is the smaller, ju st beneath the umbo, and a
third a little behind it. The ligament is externally visible, being
attached to the hinge-line above the teetli, a portion of it being
internal above and between the teeth.
48. Scintilla alberti. ( P l a t e VII. figs. G, G 1.)
Shell small, pellucid, milky white, considerably inequilateral,
transversely oblong, shorter and narrower iu front of the umbones
than behind them, moderately swollen. Lateral and dorsal margins
curved, ventral rather rectilinear. Surface glossy, exhibiting
(under the lens) distinct concentric lines of growth and also minute
radiating and somewhat interrupted striæ, visible ouly under a
compound microscope. Umbones small, slightly elevated above the
hinge-margin, not quite adjacent, the valves being closed. Cardinal
teeth insignificant, consisting of a single suhumhonal denticular
slight obtuse prominence, which is more distinct in the left than in
the right valve. Ligament small, visible externally, extending on
both sides of the apices of the beaks, but further posteriorly than in
front. Height 5 ^ millim., width 4, length 7 \.
Hab. AAest Island, Prince of AYales Channel, Torres Straits
( Coppinger).
8. hydatina, Deshayes, appears to he more closely related to this
species than to any other in the genus. H is, however, higher, more
equilateral, fiatter, with more equal sides and a curved ventral I -T
49. Crassatella pulchra.
Eeeve, Conch. Icon. fig. 16.
Hab. Thursday Island, Torres Straits,_3-4 fms. {Coppinger) ; Port
Essington {Capt. Wickham, H.N., in Brit. Mus.).
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