142 Part 111.— Twenty-first Annual Report 
The First Youne stage (Fig. 167) has none of the characters of the 
Megalops. 
The general form of the carapace and pereiopods has changed 
towards the adult condition ; the lateral teeth of the carapace are now 
present, though not fully developed. 
The integument is not so transparent as in Megalops; it now shows 
some definiteness of structure; it is not yet calcified. It is, moreover, 
covered all over the exposed surfaces with minute “ needle-point ” cilia 
(Figs. 166, 169). They are arranged singly, or in groups of two, three, 
or four. 
The carapace is longer than it is broad. 
The abdomen is tucked in under the thorax, the five pairs of 
pleopods are present in a degenerate condition. 
SEconD, THIRD, AND Fourts (Figs. 173, 170, 171). In the second, 
third, and fourth stages, with increased bulk, the carapace tends to 
become broader proportionally. The lateral teeth become more 
prominent. The eyes become less so. 
The minute ‘“ needle-point” cilia were found in all these stages. In the 
fourth stage (4 mm.) they were made out on the dorsum of the carapace. 
Crab 5:5 mm. In this crab none of the cilia were found on the 
carapace. The sexual characters were distinguished at this size. 
The cilia therefore apparently disappear between 4 mm. and 5°5 mm. 
The sexual] characters were not noticed in the ciliated individuals : 
their examination was not, however, an exhaustive one. 
The ciliated stages are probably non-sexual. 
DEVELOPMENT OF THE APPENDAGES. 
The appendages will be considered in the following order :—(1) 
Antennule, (2) Antenna, (3) Mandibles, (4) First Maxilla, (5) Second 
Maxilla, (6) First Maxillipede, (7) Second Maxillipede, (8) Third 
Maxillipede, (9) Pereiopods, (10) Branchiz, (11) Telson, Abdomen, 
Pleopods, (12) Kye. 
ANTENNULE, a., Plate vii. 
I. (Figs. 2 and 33). The antennule of the first Zoéa is 2-jointed, a 
short proximal and a long distal joint. It is of cylindrical form, and 
is slightly curved. It bears at its extremity five sensory tubes ; of these 
two are long, the others short. These tubes are connected directly with 
the ganglion which is seen occupying nearly the whole of the long 
joint. When the antennule is examined im sitw in the cephalic region 
(Fig. 33), the short first joint appears to be sunk through the integument 
into the cephalic region. 
During the remaining Zoéa stages the number of sensory tubes 
increases, and the shape of the long joint changes to a pear-shape. 
II. (Fig. 3). The aesthetascs (sensory tubes) are six in number ; 
of these one is very short, the others vary in length and thickness. 
III. (Fig. 4). In the specimen of the third Zoéa, only five aesthetascs 
were found, but they were arranged differently from the previous 
stage; four were terminal, and the fifth arose a little distance short 
of the tip. 
IV. (Fig. 6). There were now seven sensory tubes; four of these 
were terminal, and the remaining three arose together a little behind 
the other group. 
The first joint of the antennule was not noticed. The shape of the 
long joint has altered considerably, and it is now constricted at its 
