DEVELOPMENT AND LIFE HISTORY OF SOME TELEOSTS 
569 
less strongly oblique, but remains superior, and the gape is proportionately further 
removed from the eye. The notochord is bent upward sharply at the tip, giving the 
tail a heterocercal appearance. The caudal fin is fully formed, with definite rays, 
and has a nearly straight posterior margin. The soft dorsal and anal contain some 
well-developed rays, but a definite fin ray count is not yet obtainable. The pectorals 
remain as tufts of membrane, and the ventral fins (disk) are not yet evident. Pig- 
mentation has made little progress. It now consists of two or three short, narrow, 
dark lines on the chest, a very small dark spot at the vent and a slightly larger one 
at or near the end of the anal base. The crescent-shaped dark area over the air 
bladder, visible through the abdominal wall, is prominent and serves as a ready 
recognition mark (fig. 68). 
Figure 69 . — Gobionellus boleosoma. From a specimen 7.5 mm long. 
Specimens 7.5 mm long . — The body has increased somewhat in depth but remains 
comparatively very slender, the depth being contained in the length to the base of 
the caudal about 7.5 to 8.0 times. Some progress in the development of the fins has 
been made. It is now possible, in at least some specimens, to make a fairly accurate 
count of the soft dorsal and anal rays, each fin having 11 to 13 rays. The caudal fin 
is well developed and its margin is straight to slightly concave. The pectoral fins 
have indications of rays and the base of the ventral disk is just becoming evident. 
The spinous dorsal is undeveloped, or in some specimens just becoming evident. The 
notochord, sharply bent upward at its tip, remains visible. A crescent-shaped dark 
area over the air bladder is quite distinct. This dark area is visible with the unaided 
eye in somewhat larger specimens and is a definite aid in identification. Pigmenta- 
tion on the body remains virtually as in 5.0 mm fish (fig. 69). 
