86 
MR. W. K. BROOKS OK LUCIFER: 
tlie fourth abdominal segment, and the anal spots are large, with a dull red tinge. 
The spots on the carapace disappear at the end of the Zoea series. 
The Mastigopus stage. 
After the next moult the larva (Plate 7, fig. 60) assumes a form which is essentially 
like that of the adult, hut with numerous slight differences, the most important of 
which are the shortness of the flagellum of the first antenna and the absence of 
the neck or elongation of the carapace. In these respects, as well as in the number, 
character, and relative size of the appendages, it now agrees very closely with the young 
Sergestes or Mastigopus. 
The size of the thorax is reduced, while the abdomen has grown larger and longer. 
The exopodites of the maxillipeds and first three pairs of pereiopods have disappeared, 
together with every trace of the fourth pereiopod. The abdominal appendages are 
perfect; the first is made up of an elongated basal joint, which carries a single terminal 
branch of about the same length as the basal joint, but pointed and fringed with long 
slender swimming hairs. The four appendages which follow are each furnished with 
two terminal branches instead of one, but are similar in other respects. The larva now 
sheds its skin several times, and grows with each moult; but the process of change 
into the adult is, with the exception of the elongation to form the neck, simply a 
process of growth, as the appendages and somites all have essentially their adult 
character. 
A larva about one-fifth of an inch long, two moults after the last Schizopod stage, is 
shown from the side, magnified about fifty diameters, in Plate 7, fig. 60. The first 
antenna (A) is a little more than twice as long as the eye-stalk, and consists of a stout 
three-jointed basal portion, which forms about two-thirds of the total length of the 
appendage, and a short, thin, two-j ointed flagellum. The scale (ex) of the second 
antenna is only a little longer than the eye, while the flagellum (en) is more than half 
as long as the body of the animal, measured from rostrum to telson, and is made up of 
thirteen small joints and two thicker basal joints. 
The carapace has elongated considerably, and the neck ( n) makes nearly half its 
length. The anterior end of the carapace has a dorsal rostrum (R), two much shorter 
lateral spines (Is), and a very small spine on each side close to the anterior edge and 
about half way between the rostrum and the lateral spine. The cephalic lobes of the 
stomach extend into the neck, and reach nearly to the basis of the eye-stalks. The 
coiled antennal gland (g) has made its appearance. The carapace proper (c) has a pair 
of anterior spines, but none on its posterior margin. The labrum (L) has a much 
greater relative size than it had during the Schizopod stages, but its spine disappears 
at the end of the last Schizopod stage. The mouth parts and thoracic limbs have 
their adult character, and will be noticed at length in the description of the adult. 
A reddish-brown pigment-spot has now appeared between the bases of the eye-stalks; 
