BULLETIN OF THE UNITED STATES FISH COMMISSION. 429 
63. — A REVIEW OF THE MACKERELS (SCOUIRRINvE) OF A 31 ERICA 
AN© EUROPE. 
By FLETCHER B. DRESSLAR and BERT FESJLER. 
In this paper we give the principal synonymy of the genera and spe- 
cies of the family Scombrinw , found in America and Europe, together 
with analytical keys for the separation of the genera and the identifi- 
cation of the species. 
The specimens studied by us belong to the museum of Indiana Uni- 
versity, and were mostly collected by Professor David S.. Jordan. Du- 
plicate series of most of the species are in the U. S. National Museum. 
The paper was prepared under the direction of Dr. Jordan, to whom 
we are indebted for aid of various kinds. 
We adopt the family of tScombridcv as defined in Jordan and Gilberts 
“ Synopsis of the Fishes of North America.” The true mackerels belong 
to a subfamily, or perhaps family, Scombrince , which may be defined 
thus: 
Body elongate, little compressed, covered with small scales or partly 
naked; the scales about pectoral region generally enlarged, forming a 
“ corselet.” Lateral line always present, usually more or less undulat- 
ing. Head conical. Mouth terminal, rather large. Premaxillary not 
protractile; maxillary with no supplemental bone. Jaws armed with 
sharp teeth, of varying size and form. Opercles without spines or den- 
ticulations. Gill-openings wide, a slit behind the fourth gill; gill- 
membranes separate, free from isthmus. Pseudobranchim large. Bran- 
chiostegals 7. Dorsal fins separate, the spines slender, decreasing in 
length and strength posteriorly; depressible in a groove; second dorsal 
of soft rays similar to anal; soft dorsal and anal followed by a series of de- 
tached finlets. Caudal peduncle long, slender, usually with lateral keel. 
Caudal fin large, very deeply forked; caudal lobes narrow, abruptly 
diverging. Ventral fins thoracic, of moderate size, I, 5. Vertebrce nu- 
merous, 31 to 66. Pyloric coeca present, numerous. Air-bladder small 
or wanting. Sexes similar. Coloration always metallic, often very bril- 
liant. Fishes having a wide range. This definition excludes Gempylus 
and its relatives, elongate species, destitute of finlets, intermediate be- 
tween the true Scombrince aud the Trichiurince. There are in Scombrince , 
as here restricted, nine genera aud about sixty species. 
In addition to the eight below-mentioned genera is an Asiatic genus, 
Grammatorcynus , which differs from Albacora in having a double lateral 
liue and fewer dorsal spines aud finlets. 
