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DESCRIPTION OF TWO NEW INVERTEBRATED ANIMALS FROM AUSTRALIA,
BY J. E. GRAY, ESQ., F.R.S.
Lamarck separated the mother-of-pearls shell (MARGARITA) from the
swallow-tail muscles (AVICULA) on account of its more orbicular shape.
Other Conchologists have been inclined to unite them, as some of the
species of AVICULA approach to the shape of the other genus. The new one
just received from Australia, which I am now about to describe, in this
respect more resembles the Margarita than any before noticed; yet I am
inclined to think that the pearl-shells deserved to be kept separate, as
the cardinal teeth are quite obliterated in the adult shells, which is
not the case with any AVICULAE I am acquainted with; and the young
pearl-shells are furnished with a broad serrated distant leafy fringe,
while the AVICULAE are only covered with very closely applied short
concentric slightly raised minutely denticulated lamina, forming an
epidermal coat on the surface.
1. AVICULA LATA, pl. 6. f. 1.
Shell dark brown; half ovate; broad obliquely truncated, and scarcely
notched behind; covered with close regular very thin denticulated
concentric lamina, forming a paler external coat. The front ear rather
produced, with a distant inferior notch; internally pearly, with a broad
brown margin on the lower-edge.
Inhab. North and West coasts of Australia.
2. SPATANGUS ELONGATUS, pl. 6. f. 2.
Body elongate, cordate, with a deep anterior grove and notch; covered
above with minute hair-like spines, with scattered very elongated tubular
minutely striated spines on the sides; the anterior groves and
circumference of the vent with larger equal hair-like spines on each
side; the under surface with a triangular disk of similar spines beneath
the vent, and with elongated larger tubular spines.
