SYNOPSIS OF THE FISHES OF MADEIRA. 19 



secunda majore postica, caudie approximata. Pinna analis nulla- Pinna ventrales 

 subpostica; s. secunda; dorsali subanteriores. 



Denies utriusque maxillse 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. " Gatu 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. 



AcANTHiDiUM CALCEUs. " Sopata." A. purpureo-fuscuiu, subtus palUdius : rostro 

 plano-depresso : dentibus inferioribus biseriatis : spiraculis oculo, pinndque dorsali 

 secunda caudtE approximatis. 



Centrina Salviani, Syn. Mad. Fish, in Trans. Zool. Soc. p. 194 : nee aUorum. Rarior. 



* 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 (/ectius ventral) 

 fin, and the form of body of the latter." 



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