22. Petricola lapicida.
Venus lapicida, Chemnitz, Con.-Cah. x. p. 356, figs. 166fo5 ; Soiverhy,
Conch. Icon. (Petricola) figs. 22, 24 ; Martens in Von der Dechen s
Reisen in Ost-Afriha, vol. iii. p. 66, pi. 3. figs. 3 a, h.
Hah. AVest Indies (Chemnitz, d’Orhigmj, 4'c.) ; North Australia
( / . R. Elsey in Brit. Mus.) ; AVest Island, Prince of A\*ales Channel,
Torres Straits ( Coppinger) ; Zanzibar (Peters, teste Alartens).
This and the Venus divaricata of Chemnitz I, regard as one species,
and from his description of the former it seems probable th at he had
before him specimens which to a great extent had lost the fine zigzag
sculptnro mentioned in his description of the latter. The raised
oblique ridges from the umbones down the posterior slope have
various degrees of development in different specimens, iu some existing
onl}' near the posterior margin of the valves, whilst in others they
extend the whole distance from the beaks downivards, and, again, in
young shells they may be altogether Avanting. These ridges are
easily removed, and seem to he superimposed upon the zigzag sculpture
beneath. After a careful examination of Australian specimens
and others from the AA*est Indies, I cannot detect any material
specific differences.
The example figured by Dr. E. von Martens as P. divaricata is
iinsnally peaked at the umbones.
23. Psammohia modesta.
Deshayes, Proc. Zool. Soc. 1854, p. 319 ; Reeve, Conch. Icon. tig. 3.
Hah. Port Jackson (Coppinger) ; Moreton Bay (Deshayes).
Tho single specimen before me is rather narroAver than th at
flo-ured in the ‘ Conchologia Iconica,’ is purplish lilac within for the
ruost part, yellowish near the muscular scars, and exibits the pinkish
rays on tho ventral margin. The epidermis is brightish yellow.
Oblique striæ are sometimes present at the central portion of the
valves, but are not conspicuous.
24. Psammohia gracilenta. ( P l a t e VII, figs. B-B 2.)
Shell concentricaBy striated, transversely elongate, very inequilateral,
almost twice as long as high, not very compressed, dirty
whitish with a few diaphanous zones and several light reddish
narrow rays beneath a thin pale yellowish-olive epidermis, very
narrowly gaping at both ends. Anterior dorsal margin of the valves
about twice as long as the posterior, subrectilinear, and nearly
parallel with the ventral. Hinder dorsal edge oblique, a little
arcuate. Lower margin straightish, obliquely curving upward in
front and more sharply turning at the opposite extremity. Interior
bluish white, iridescent, exhibiting the reddish rays. Beaks small,
adjacent, posteriorly inclined. Ligament short, hut prominent, placed
on a conspicuous ligamental plate in each valve behind the umbones.
A second minute ligament exists immediately in front of them and
is partly enclosed when the valves are shut. Cardinal teeth two in
each valve, those of the right most prominent. Front dorsal margin
of right valve narrowly grooved just Avithin, simple in the left.
Corselet linear. Posterior muscular impression rotund-pyriform,
anterior more elongate. Pallial sinus moderate, extending forward
beyond the middle of the valve. Length 1 9 | millim., height 10,
diam. 5.
Hab. Prince of Wales Channel, 9 fms.
A very elongate narrow species, recalling to mind certain slender
forms of the genus Donax.
25, Tellina semen.
Hanley, Thesaurus, vol. i. p. 249, pi. 56. fig. 8 ; (? Sowerby, Conch.
Icon. vol. xvii. fig. 232, bad!).
Hah. Thursday Island, Torres Straits, in 5 -7 fms.
Among the specimens from this locality is one of a purplish-rose
tint, the rest being white like the type. The hinge of this species
is composed of two cardinal teeth in the right valve (the posterior
one larger and bifid, with one lateral tooth on each side and a groove
between it and the m argin), and of a single bifid cardinal in the left
valve with a marginal lateral tooth or prominence on each side. The
pallial sinus is very large, almost reaching to the anterior scar.
The form of this species is very similar to th a t of T. obtusalis,
Deshayes, which is the same as T. malaccana, Sowerby (Con. Icon,
figs. 281 a and 125). The posterior end, however, is not so obtuse
and the form is not so like th at of a Donax. In T. obtusalis the
concentric striæ are rather coarser than in the present species, and
become very much finer anteriorly, so th at in th at part the shell is
more glossy and comparatively smooth, which is not the case in
T. semen. Another form, T. semitecta, Sowerby, from New South
Wales, is very closely related to the present species, and is mainly
distinguished by its rather more elongate form, and finer and less
elevated sculpture at the hinder extremity.
26. Syndosmya elliptica. ( P l a t e Y II. figs, C, C 1.)
TeUina elliptica, Sowerby, Conch. Icon. fig. 223 (bad!).
Hah. Port Jackson (Angas and Coppinger).
The type and a second specimen of this species were presented to
the British Museum by Mr. Angas in 1871. Neither of these nor a
third collected by Dr. Coppinger exhibit the sinuation at the posterior
end of the ventral margin depicted in Sowerby’s figure. His
words “ concentrically ridged behind the angle ” are scarcely applicable,
for in the first place there is only the feeblest indication of an
angle and the sculpture behind it consists of mere concentric striation.
The hinge-characters show this species to belong to the genus
Syndosmya, and Tellina simplex of the same author (Conch. Icon,
sp. 240) requires a similar location. The hinge of the present species
consists of two cardinal teeth iu the right valve, the posterior larger
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