14 PROCEEDINGS OF THE ACADEMY OP 1 D. fcl. 2, 16, 2. A. 14 -. C. 4, 5, 4, 3. P. 16. V. I. 4. 1 The ahdomen is spotted. The preopercular, interopercular and suborbital regions, the membrane connecting the maxillary bones and the lower surface of the head, are covered with large dark brown dots. The fins are more or less distinctly banded or spotted; the ventrals whitish. Specimens of this species were obtained by Dr. Kennerly, the naturalist of the North-Western Boundary Survey, and are also found at San Francisco, a large specimen being in the same lot containing the true Hemilepidotus spinosus, and confounded with it by Dr. Girard. From that species it differs in the number and arrangement of the cutaneous tags as well as by color. I have dedicated the species to my friend, Mr. George Gibbs, who rendered much valuable assistance to the naturalist of the Survey. A detailed descrip-tion will be given in the Report on the Ichthyology of the Western Coast. On the Subfamily of ARGENTININJE. BY THEODORE GILL. In the " Catalogue of the Fishes of the Eastern Coast of North America," the family of Salmoaoids is divided, with Prince Bonaparte, into two sub-families, the Salmoninae and Argentininae, but with the very important modification of the exclusion from the latter, as well as from the family itself, of the genus Microstoma. With Bonaparte also Osmerus is retained among the Salmonina?, while Mallotus is placed in the subfamily of Argentininas. The great error involved in this arrangement was subsequently discovered, but I unfortunately forgot to correct it in the Catalogue. The only character which thus separates the two subfamilies is the development of the teeth, a charac-ter of secondary value. The two subfamilies are very distinct from each other, but distinguished chiefly by the modifications of the intestinal canal. The Salmonince have the stomach nearly or quite siphonal, and the pyloric caeca are numerous. The Argentininae have the stomach decidedly caecal, and the caeca are gene-rally five in number, and surround the pyloric extremity of the stomach. Dr. Kner, in his excellent contribution on the form of the stomach and the development of the pyloric caeca, has even suggested that Osmerus and its allies may belong to a different family ; and it certainly appears quite pro-bable that such is the case. The position of the Argentininae, as a subfamily of the Salmonoids, is therefore provisional. The Argentininae, as now characterized, are divisible among two distinct groups ; one has the normal salmonoid position of the dorsal fin, or, in other words, it is subcentral, and above or nearly above the ventrals. This group embraces all the common northern or European and American species. Another group, represented by a single species, is distinguished by the pos-terior insertion of the dorsal and its position above the anus; the species is an inhabitant of Australasian seas, and has been described under the name of Argentina retropinna, by Sir John Richardson. The specific name may be ac-cepted as a generic appellation, while the species can be called in honor of its learned describer, Retropinna Richardsonii. A species of the true Argentine group also is the type of a distinct genus nearly allied to Argentina;, with which it agrees in the number of brancbios-tegal rays, but the mouth is larger, the dentition different and the ventral fins more advanced. Its type is the Argentina pretiosa of Girard, or Osmerus elonga-tus of Ayres. It may be named Mesopus, in allusion to the position of the ventral fins. The following synopsis exhibits the relations and differential characters of the several genera : Jan.