146 
BUULETIN OF THE BUREAU OF FISHERIES. 
The spawning habits vary, both as to season and as to the character of environ- 
ment preferred, but none of the species is known to spawn in waters of a greater 
depth than 5 fathoms. In all known cases the eggs are minute, transparent, and 
buoyant, containing one or more oil globules within the yolk. Under normal 
circumstances the eggs float freely at or near the surface during at least a part of 
the period of incubation and are carried about by the currents. There are indica- 
tions that spawning takes place chiefly at night. The period of incubation, at 
water temperatures of 65° F. and over, is short, seldom over 48 hours in the species 
that have been studied. 
The newly hatched fry are minute, transparent, and practically helpless, 
drifting about for the first few days in an inverted position, owing to the location 
of the bouyant oil globule in the posterior ventral region of the yolk sack. After 
the absorption of the yolk the growth is usually rapid, spring-hatched fry often 
doubling their length within 30 days during July and August. The growth of fry 
hatched during the fall and winter months is very slow until the following spring. 
The size at which the young begin to resemble the adults in form and color 
pattern varies greatly among the several species, the most precocious forms being 
Larimus and Menticirrhus. In all species the very young differ from the adults 
in having the head and eye larger and the vertical fins much higher in proportion 
to the body length. 
The growth throughout life is most rapid in the summer months and practically 
ceases in the winter, even in southern waters. The annual growth is greatest 
during the period of immaturity, decreasing rapidly after the first spawning and 
normally becoming less each year thereafter. So far as known spawning occurs 
every year after maturity is attained. The age at the time of the first spawning 
varies, according to species, from one year (Stellifer) to three or four (Micropogon 
and others) and in some cases possibly more. In certain species the males appear 
to mature a year earlier than the females of the same age. The material available 
is insufficient for a reliable determination of the average and extreme ages attained, 
but a thorough study of the scales would probably throw much light upon this 
subject. 
KEY TO SCIiENIM OF ATLANTIC COAST. 
The key included in this paper has been designed chiefly for the nontechnical 
man who may want a ready aid to the identification of the species of this family 
encountered. With this point of view in mind, the key was constructed with the 
use of external characters only, or such that are readily accessible without the aid 
of dissecting instruments or a knowledge of their use. This, of course, prevents 
the identification of greatly mutilated specimens; but a person not trained in such 
work would do better to submit such material to institutions that are qualified 
for the identification of fragmentary material. It is believed, however, that no 
one should have difficulty in using this key with the supplementary aid of the 
accompanying illustrations of adult and immature fish. 
All technical terms are explained in the glossary and diagram (fig. 1) that 
precede the key proper. The diagnosis of the family will eliminate any specimens 
somewhat resembling Sciaenidae known from the Atlantic coast. 
