The specimens examined are listed under each species description with their catalogue numbers, sizes, and localities. The abbreviations prefixed to the catalogue numbers indicate the following institutions and collections where those specimens belong:

ABE:

Dr. T. Abe's personal collection, Tokyo

BMNH:

British Museum (Natural History), London

BPBM:

Bernice P. Bishop Museum, Honolulu

FAKU:

Faculty of Agriculture, Kyoto University

FSFL:

Far Seas Fisheries Research Laboratory, Shimizu

HUMZ:

Laboratory of Marine Zoology, Faculty of Fisheries, Hokkaido University

MIKU:

Misaki Marine Biological Institute, Kyoto University

MNHN:

Museum National d'Histoire Naturelle, Paris

RMNH:

Rijksmuseum van Natuurlijke Historie, Leiden

SMF:

Senckenberg Museum, Frankfurt am Main

TUFO:

Tokyo University of Fisheries

UG:

University of Guam

UMUTZ:

Department of Zoology, University Museum, University of Tokyo (Specimens of earlier numbers used to be kept in the Zoological Institute, Faculty of Science of the same University.)

ZMHU:

Zoologisches Museum, an der Humboldt Universitat zu Berlin

ZMK:

Zoologisk Museum, København

The catalogue numbers of dried specimens are followed by the letter D in parentheses.

The methods of measuring and counting and the terminology are mostly the same as those explained by Hubbs & Lagler (1947). In this group the scale row number between the lateral line and the dorsal fin is smallest under the middle of the spinous portion (Fig. 1), and far more stable there for each species than under the origin of dorsal fin where such counts are usually made in other groups. This number was adopted by Bleeker (1873a) and Klunzinger (1884) as a good key character because some species have 5 rows there while others have 6 rows, though a few species show individual variation between 5 and 6. Figure 1 also illustrates some other characters described in the present work.

Approximately half of the species of this genus have a patch of small scales on the inner side of the base of pectoral fin (Fig. 2) while the rest do not. The presence or absence of such scales can easily be confirmed by turning the fin forward, and is therefore a clear key character. However, this character is hard to use in the case of dried specimens in which the pectoral fin is not movable. Furthermore, in many of the stuffed specimens made in the 19th century, the inner base of the pectoral has been destroyed in the process of stuffing.

Günther (1859) found that the shape of teeth on the jaws is another good key character in this genus. Every species can be assigned either to the group with molars on the lateral side of the jaws or to the group with only conical teeth there, though this character can hardly be applied to individuals less than 10 cm in total length. Shapes of the teeth in some species are shown with terminology in Figure 3.

Distribution patterns of the melanophores on pelvic fin membranes are also described as a key character in the present work. Figure 4 shows three typical patterns in this genus. It is difficult to observe such patterns with the naked eye. A piece of white paper is also necessary to apply against the spread pelvic fin. In old discolored specimens, melanophores may be observed as whitish dots instead of black ones but are always observable unless the fin has been broken.

For the other key characters which need some explanation, illustrations are given in the key to the species.