DEVELOPMENT AND LIFE HISTORY OF SOME TELEOSTS 
511 
related, and the young may not be separable. Nevertheless, it seems highly probable 
that we are dealing with Spanish mackerel only, as shown subsequently. 
The descriptions that follow are all based on preserved specimens. Considerable 
shrinkage takes place during the hardening process. Consequently the smallest larvae 
herein described, though shorter than the largest ones described by Ryder (1882) in 
the fresh state, are more advanced in development. 
Specimens about 2.5 mm long . — The body is robust, but the tail is long and slender, 
being notably longer than the head and trunk. The greatest depth is contained in 
the total length about 3.25 times. The mouth is very large and broad and strongly 
oblique; the gape reaches under the eye; and the lower jaw projects slightly and is 
straight and broad. Teeth already are plainly visible. The myomeres are indistinct 
anteriorly and posteriorly and therefore cannot all be enumerated. They appear to 
be rather numerous. Slight indications of rays are present above and below the tip 
of the tail. Pectoral fin membranes are prominent, with indications of rays. 
The general color of the preserved specimens is brownish. A dark spot just 
behind the symphysis of the lower jaw is at least sometimes present, and another one 
appears on the abdominal wall a short distance in advance*of the vent (fig. 2). 
£ The chief distinguishing character, and the one that seems to “link” these larvae 
with) the smaller and larger ones, is the large broad oblique mouth with well developed 
teeth. 
Specimens 3.0 to 3.5 mm long . — The caudal portion of the body has grown pro- 
portionately much shorter and deeper, the vent now being situated near midbody 
length, and the greatest depth is equal to the head, and is contained about 3.0 times 
in the 1 ; length. The mouth remains large and wide, and has become more strongly 
oblique. Two depressions, one over the snout and another at the nape, are present 
and rather more prominent than in the smaller fish already described. Several 
prominent spines are present on the preopercular margin (which disappear in the 
adult). Three slender spines are developed in the anterior part of the dorsal finfold, 
though no soft rays are developed, a sequence contrary to that found in other species 
studied, and apparently contrary to the general rule in spiny-raj^ed fishes, in winch 
the soft rays most usually are developed before the spines appear. A variation in the 
relative length of the dorsal spines seems to exist among individuals of about this 
size and larger ones, as in some specimens the first spine is longest and in others the 
second one. 
A few dark spots are present along the ventral surface of the caudal portion of the 
body, and generally some dark markings appear on the dorsal wall of the abdominal 
cavity (figs. 3 and 4). 
