LOWE, R.T. 1839
A supplement to a synopsis of the fishes of Madeira.
Proceedings of the Zoological Society of London, 7: 76-92
Page 1
TRANSACTIONS
OF
THE ZOOLOGICAL SOCIETY.
I. Supplement to "A Synopsis of the Fishes ofMadeira*" By the Rev. R.T. Lowe,
M.A., Corr. Memb. of the Zool. Soc.
CommunicatedMay 28, 1839.
Page 18
Gen. ACANTHIDIUM.
Corpus gracile, elongatum. Spiracula magna. Pinnae dorsales duae, antice spiniferae;
Page 19
SYNOPSIS OF THE FISHES OFMADEIRA. 19
secundà majore posticâ, caudae approximata. Pinna analis nulla. Pinnae ventrales
subposticae s. secundae dorsali subanteriores.
Dentes utriusque maxillae dispares, parvi: superioris laniarii, plano-triangulares, tenues,
acuminati; acumine recto; basi utrinque denticulo aucto; antice triseriati, lateribus
biseriati: inferioris incisorii, acumine utrinque a medio oblique deflexo, uni- vel bi-se-
riati. Cauda oblique oblonga, apice truncata.
This new genus appears exactly intermediate between the established genera of
Cuvier, Spinax and Centrina: agreeing with the former in its elongated form, and with
the latter in the teeth.
The ventral fins are placed more backward than in Spinax, but rather forwarder than
in Centrina, i. e. neither halfway between the two dorsal fins, nor opposite the second
dorsal fin, but just before the second dorsal fin, which begins exactly opposite the ter-
mination of their base. The tail or caudal fin resembles that of Spinax rather than of
Centrina, and the spines of both the dorsal fins are reflexed as in Spinax, forming the
fore-edge of each fin. The pectoral fins are abruptly truncate. The second dorsal fin
is greatly larger than the first; in which it differs equally from Spinax and Centrina.
The teeth are not arranged quincuncially, but behind each other in rows.
Two species have occurred, both of which have hitherto been confounded with Cen-
trina.
ACANTHIDIUM PUSILLUM. "Gata negra." A. totum atrum, pusillum: rostro cras-
siusculo: dentibus inferioribus uniseriatis: spiraculis oculo remotiusculis.
Centrina? nigra, nob. olim in Proceed. Zool. Soc. 1833, p. 144*. Syn. Mad.Fish,
in Trans. Zool. Soc. p. 194. Rariss.
Four individuals of this curious little shark have now occurred, agreeing equally in
the foregoing characters and in their dimensions, varying in length only from eleven to
twelve inches. The second dorsal fin is somewhat forwarder or more distant from the
origin of the tail than in the next species.
The condition of the teeth, and constancy of size, both indicate an adult fish; and a
comparison of the present species with the foetal and adult state of the following, in
these two points alone demonstrates Acanthidium pusillum to be no stage of A. calceus.
* A serious erratum has been caused here by the transposition of a sentence. The paragraph referred to
should stand thus : " It (Centrina ? nigra) is intermediate in characters between Centrina, Cuv., and Acanthias,
Risso, having the teeth of the former genus as well as the backward position of the second dorsal (rectius ventral)
fin, and the form of body of the latter."
