132 SCOMBRID.E. 



cant/ius and Alepisaurus.* The " slendemess and concealment of the 

 maxiUary, and thickness of the upper lip" (Cuv. and VaL Hist. xi. 

 173) are equally inconsequential ; or, when compared with certain genuine 

 ScombridfE, absolutely null as differential characters, however they may 

 have aided in suggesting to the older Ichthyologists the approximation 

 above mentioned. In short, the relation of Tetragonurus with the Mu- 

 gilidae is at most one only of transition, if indeed one of more than mere 

 analogy: whilst with Scombrida, Cuv., through Aphirus and Thyrsites^ 

 it agrees no less in all essential points of structure both internal and 

 external, than it does in habit, form, and colouring. 



To speak more definitely, Tetragonurus is Thyrsitoideo-Scombridal, 

 or allied to the Thyrsitoid Scombridse, in its elongated form, large 

 branchial opening, mouth, and gape ; in its uniformity of colour, and 

 large opaline dark eye ; in the number of accessory rays above and be- 

 neath, and the lateral keels, at the root of the caudal fin ; in the po- 

 sition, shape, and character of the dorsal and anal fins ; in the whale- 

 bone-like nature and strongly barred or knuckled structure of the soft 

 rays in all the fins ; and lastly in the long, simple stomach, numerous 

 vertebra and caca. The teeth also in their shape, and in their pre- 

 sence on the palatines and vomer, agree, like the anatomy, precisely 

 with Thyrsites. 



Thus, on this cumulative evidence, and with the exception of the ctenoid 

 scales, Tetragonurus proves, as from the discovery of the cognate Aplurus 

 I suspected-f- long before seeing (as it appears) a genuine species, at least 

 as properly Scombridal as Thyrsites, Cuv. : and since Aplurus^ scarcely 

 differing generically from Thyrsiles, offers in the dermal characters, already 

 so remarkable, an instance of anomaly amongst the Scombrida, there 

 seems no occasion, after Risso, to consider it the type of a peculiar family, 

 " les Tetragonvirides,"" Risso. 



The only individual of the Madeiran fish which has occurred, was 

 taken by a fisherman of Camera de Lobos, a village three or four miles 

 to the westward of Funchal, on the 28tli of June 1838 : who assured me 

 that he had caught it swimming on the surface, with his hand ; an ac- 

 count which, corroborated by the absence of all injury from the hook 

 about the mouth, better corresponds with M. Risso's statement of the 

 feeble swimming powers (" faible natation") of his fish, than with M. 

 Laurillard's of its activity (" vivacite de ses mouvements'''').| Since 

 all about its history and structure indicate, however, a pelagic fish, whilst 

 nothing either in its organisation or affinities would denote departure from 

 the usual habits of its tribe, it is extremely probable that the alleged cir- 



* Tlie affinities of both these genera arc doubtful : yet the fonner is, like Lunipris, included in 

 !Scombrkl<B by MM. Cuvier and Valenciennes : which is suilicient t'tn- the j)resent argument, 

 t Sec Proceed. Zool. Soc. 1833, 1, 143. X Cuv. and Val. Hist. xi. ltJ4. 



