230 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [524] 
cephalothoracic legs (g, h, ¢) are all similar and of about the same size, 
except the main branch of the first pair, (g,) which is much larger than 
that of the others, but is still sack like and entirely without articula- 
tions. The outer or exopodal branches of all the legs are slender, wholly 
unarticulated, sack-like processes, while the inner or main (endopodal) 
branches of the four posterior pairs are similar, but much stouter and 
slightly longer processes arising from the same bases. The bases of all 
the legs are marked with dendritic spots of red pigment like those upon 
the lower margin of the carapax. 
The abdomen (m) is curved round beneath the cephalothorax, the 
extremity extending between and considerably in front of the eyes. 
The segments are scarcely distinguishable. The extremity, as seen from 
beneath the embryo, is slightly expanded into a somewhat oval form, 
and very deeply divided by a narrow sinus, rounded at the extremity. 
The lobes into which the tail is thus divided are narrow, and somewhat 
approach each other toward the extremities, where they are each armed 
along the inner edge with six small obtuse teeth. 
The heart (1) is readily seen, while the embryo is alive, by its regular 
pulsations. It appears as a slight enlargement in the dorsal vessel, 
just under the posterior portion of the carapax. The intestine (k) is 
distinctly visible in the anterior portion of the abdomen as a well defined, 
transparent tube, in which float little granular masses. This material 
within the intestine is constantly oscillating back and forth as long as the 
embryo is alive. 
The subsequent development of the embryo within the egg was not 
observed. The following observations on the young larvee, after they 
have left the eggs, have all been made upon specimens obtained in Vine- 
yard Sound, or the adjacent waters, during July. These specimens were 
mostly taken at the surface in the day-time, either with the towing or 
hand net. They represent three quite different stages in the true larval 
condition, besides a later stage approaching closely the adult. The 
exact age of the larve of the first stage was not ascertained, but was 
probably only a few days, and they had, most likely, molted not more 
than onee. Between the third stage, here described, and the last, there 
is probably an intermediate form wanting. 
First stage.—In this stage, (Plate LX, Figs. A, B,C, D,) the young are 
free-swimming Schizopods about a third of an inch (7.8 to 8.0™") in 
length, without abdominal appendages, and with six pairs of pediform 
cephalothoracie appendages, each with the exopodus developed into 
a powerful swimming organ. The general appearance is represented 
in the figures. The eyes are bright blue; the anterior portion and the 
lower margin of the carapax and the bases of the legs are speckled with 
orange; the lower margin, the whole of the penultimate, and the basal 
portion of the ultimate segment of the abdomen, are brilliant reddish 
orange. ' 
The antennule (Fig. C.) are short and sack-like, with a single articu- 
