ynoe).

...

Chelmon marginalis. RICHARDSON.

Chelmon marginalis, Richardson, Annals and Mag. of Nat. Hist. 10, page
28, September 1842.

RADII. D.9 : 31; A. 3-2l; C. 17 3/3; P. 16; V. 1 : 5.

FISHES. PLATE 4. Natural size.

This fish is described in the Annals of Natural History from a dried
specimen brought from Port Essington by Mr. Gilbert. It has very much the
form of Chelmon rostratus, but wants the eye-like spot on the dorsal.
Several examples in spirits were brought by the officers of the Beagle
from the north-west coast of Australia, all of which show a broad band
passing between the dorsal and anal fins, which was not visible in the
dried specimen. This band is bounded anteriorly by one, and posteriorly
by two whitish lines. In the Annals the anal fin is described as being
more angular than the dorsal, but in the specimens in spirits the reverse
appears to be the case. This variation depends on the degree or expansion
of the fins, and both may be much rounded by pulling the rays apart. The
exact distribution of the bands may be clearly made out from the figure,
which is very correct. The rays of the fins probably vary in number in
different individuals, and our careful enumeration of those specimens
kept in spirits, as recorded above, gives two or three soft rays more in
the dorsal and anal, than we were able to detect in the dried skin.
Length, 5 1/4 inches.

HABITAT. Northern and north-western coasts of Australia.

...

ASSICULUS.

CH. GEN. Corpus compressissimum, assulaeforme: caput crassius, minus
altum, declive. Os parvum. Maxilla inferior porifera, ore clauso
ascendens, hinc, ore hiante, ultra maxillam speriorem modice protractam
extensa.

Preoperculum margine integro nec spinifero, disco arcto, inaequali,
esquamoso, genam squamosam postice et infra cingens. Operculum
tridentatum: Suboperculum crenatum; utrumque et interoperculum
latiusculum squamis satis magnis tecta. Dentes villiformes, minuti cum
dente canino in media utroque latere maxillae inferioris et trans apicem
utriusque maxillae dentibus quatuor (vel sex) fortioribus, altioribus, in
serie exteriori ordinatis. Dentes vomeris et palati acuti, stipati
minuti. Dentes pharyngei, acerosi inequales, acuti.

Membrana branchialis radiis sex sustentata, interoperculis liberis,
accumbentibus tecta.

Squamae satis magnae, nitidae ciliatae. Linea lateralis antice abrupte
ascendens, dein dorso parallela et approximata, postice diffracta
i