of the Fishery Board for Scotland. 83 
The little hairs on the propodite and dactylopodite are probably sensory. 
Fig. 64, 7b., gives a dorsal view of the telson. 
VARIATION OF THE MEGALOPS. 
A typical megalops may be described as follows. It walks about by 
means of the pereiopods, which are now of the adult form, and it swims 
by means of its large pleopods. The exopodites of the thoracic appen- 
dages are present, but in varied structure. They may be setose, or 
much reduced, and without sete. The antenne now project as far in 
front as the chelze can reach, and are used, as in the adult, asfeelers. The 
rostrum is bifurcate at the tip. The eyes, like those of the zoca, are 
very large. 
The megalops varies in several ways—the following were specially 
noted :— 
(1) It as often as not has one or more of the dorsal abdominal 
hooks of the zoéa persisting. 
(2) It may have the median spine on the hind border of the telson—a 
zoea character. 
(3) The exopodites may vary very much. Some or all of them may 
be setose, or they may be reduced to little processes, as in the first voung 
stage. The exopodite of the first pereiopod does not usually have any 
setee. 
The following Table gives an analysis of 12 megalopa with respect to 
three characters. The sign + signifies the presence, and — the absence, 
of the character ; if no sign is entered the character had not been noted. 
Dorsal Hooks| Median | Exopodites—| Exopodites 
on Spine on some reduced to 
Abdomen. | Telson. Setose. small pro- 
cesses. 
4 Megalopa, + + 
1 Megalops, + + 
5 Megalopa, - + 
1 Megalops, a 
1 Megalops, + 
Forms Resuitinc From THE Castine oF III. anp “IV.” Zoim, 
Particulars were kept of various casts of the III, zoéa and of the 
“TV.” stage. The resulting forms were observed, and are entered in the 
following Table :— 
| TABLE. 
