_Corpus altum, rhomboideum, valdè compressum, squamis minutissimis
obtectum. Linea lateralis anticè sursum paulò arcuata, per totam
longitudinem inermis. Cauda lateribus haud carinatis. Dentes in
utrâque maxillâ uniseriati, tenuissimi, acuti; in linguâ, vomere, et
palatinis, velutini brevissimi. Apertura branchialis amplissima,
membranâ decem-radiatâ. Spinæ quinque liberæ loco pinnæ dorsalis
primæ; spinâ minutâ, præeunte reclinatâ antrorsum flexâ. Dorsalis
secunda, æquè ac analis, continua, sine pinnulis falsis: ante analem
spinæ duæ liberæ. Pectorales parvæ. Ventrales nullæ. Caudalis
profundè furcata, lobis acuminatis, subelongatis._
This new genus belongs to that section of the _Scombridæ_ characterized
by having a number of short free spines, instead of a first dorsal fin.
It is most nearly allied to _Lichia_, especially to the _L. glaucus_,
which it resembles in general form, as well as in many of its particular
characters. It has the same reclined spine in front of those which
represent the first dorsal, and the same two free spines in front of the
anal; also the same form of opercle; the same deeply forked caudal, and
small pectorals. But it may be at once distinguished from that genus by
the absence of ventrals, of which there is not the least trace: the body
is also deeper, rhomboidal rather than oval, and more compressed. In all
these respects it agrees better with _Stromateus_, which would seem
particularly to meet it in those species, such as the _S. candidus_ and
_S. securifer_, which are represented by Cuvier and Valenciennes as
having a number of minute truncated spines before the dorsal and anal
fins, and which, by virtue of this character, though in the case of the
former the spines are not apparent externally, serve manifestly to
re-conduct to the section to which _Lichia_ belongs. The discovery of
the present genus, therefore, furnishes a more completely connecting
link between these two groups.
_Rhynchobdella_ and _Mastacemblus_ agree with _Paropsis_, both in
wanting ventrals and in having the first dorsal represented by free
spines; but the form of these two genera is so totally different in all
other respects, that it is impossible they can be confounded with it.
This new genus is from the east coast of South America.