APPENDIX. 409 



the caudal ; towards its base it is broad, compressed, long and articulated : 

 the three following rays are considerably shorter, anal fin is riot quite half 

 as long an its front rays) as the second dorsal, and commencing beneath 

 the fourth dorsafspine; ventral fin rather before the pectoral, the rays about 

 twelve, very fragile, and all broken. The number of rays were as follows : — 



ARGYRIOSUS triacanthus. 



First dorsal fin small,, triangular^ of three connected rays 

 behind which are three naked spines ; anterior rays of 

 the second dorsal^ and of the anal fins of equal length, 

 the latter commencing opposite the first dorsal. 



Argyriosus Vomer. Spix and Agass. Fishes of Brazil, pi. 58. 



Under the above provisional name I shall here designate 

 what is certainly a third species of this little group, if the 

 figure given in the beautiful work of MM. Spix and Agassez 

 is not most glaringly inaccurate, a supposition and a censure 

 which there is no ground for entertaining. I omit, however, all 

 mention of the ventral fin, for the reasons already stated, in the 

 specified character, although it may be as well to mention in 

 this place, that it is represented as very short and falcate ; the 

 first, or lowest ray, being a little more than one third the 

 length of the pectoral fin. 



The first dorsal fin has three rays, but possesses this great peculiarity, 

 that the first ray is the longest, the two others rapidly decreasing, so as to 

 render the fin perfectly triangular : then follow three other naked spines 

 before the second dorsal ; thus making the total number of rays, anterior 

 to this latter fin, six, instead of eight, as in the fish described by Cuvier. 

 The long anterior rays of the second dorsal and of the anal fins are 

 of equal length; but from the very forward position of the latter, they 

 do not terminate equally, that of the dorsal comes almost in aline with 

 the end of the fcaudal, but the long ray of the anal fin only reaches to just 

 beyond the base of the tail : the anal fin is so near the head as to commence 

 on a line with the first ray of the anterior dorsal ; a structure alone which 

 will distinguish this from the two preceding species. Finally, it may be 

 observed, that the general outline of the body is more angulated ; the 

 broadest part is just above the eye, from whence the contour makes a gra- 

 dual slope. The profile also of the belly is more angular ; sloping down- 

 wards from the mouth to the base of the anal fin, and then upwards to the 

 base of the tail : there is a short spine connected to the base of the anal 

 fin, but none is mentioned at the corresponding dorsal. 



SCOMBER undulatus. 



Sides of the back marked by undulated angulated bands^ 

 with shorter lines in the interstices; sides of the 

 body unspotted; dorsal finlets siX;, the two last longest, 

 and approximating ; first dorsal of nine rays, the last 



