A STUDY IN' MORPHOLOGY. 
95 
In the adult (tig. 64) the scaphognathite is absent; the endopodite is rudimentary 
and the second joint of the base (2) is very much wider than the first (1), and has 
fifteen cutting hairs arranged in three rows, while the first joint has only four very 
much longer serrated cutting hairs. The basal joint has only one plumose hair as 
before, but the second joint has one on each side of the blade. 
The second maxilla. 
The second maxilla is present as a bud (fig. 24, Mx. 2) in the egg, and it becomes 
functional in the first Protozoea, and persists without very much change to maturity. 
In the first Protozoea (fig. 31) it has a long, many-jointed basal portion (h), with slender 
simple hairs on its inner edge ; a two-jointed endopodite ( en ) with three simple hairs 
on its tip, and two on the second joint; and a small scaphognathite with plumose 
hairs. 
In the last Zoea (fig. 47) the hairs on the inner edge are plumose, and one of 
the three hairs on the small scaphognathite is much longer than the others. 
In the Schizopod stage (fig. 53) the limb is thick and long, the scaphognathite is 
rudimentary, and the endopodite is small, and has no terminal hairs. 
In the adult (fig. 6*7) the endopodite and all but three of the joints of the basal 
portion are absent. The first of these (3) is the largest and has a broad edge, with a 
number of cutting hairs, while the others (2 and 1) are narrow and have three hairs 
each. All these hairs are simple. The scaphognathite is elongated, and is now about 
as long as the body of the appendage, to which it is joined by a narrow neck. The 
inner end has four plumose hairs, three of which are about as long as the appendage, 
while the fourth was short and apparently broken in all the specimens which I 
examined. The outer half of the scaphognathite has three short straight plumose 
hairs on its outer end, and five somewhat longer ones on its inner side. 
The first maxilliped. 
The first maxilliped is represented by a bud in the egg Nauplius (fig. 21 Mp. 1) and 
it becomes functional in the first Protozoea and then consists (fig. 32) of an unjointed 
exopodite (ex) with four long terminal hairs ; a four-jointed endopodite (en), with three 
long terminal simple hairs, and a shorter hair springing from the inner edge of each 
joint; and an obscurely two-jointed basal portion with short simple hairs on its inner 
edge. 
In the Zoea stage (fig. 48) the hairs on the inner edge and on the exopodite are 
plumose, and the endopodite is long and six-jointed. 
In the Schizopod stage (fig. 50, Mp. 1) the joints are obscure; the exopodite 
is nearly as long as the endopodite; all the hairs are plumose, and about equal in 
length, and there is a double row along the inner edge of the appendage. 
