150 Part ITT.— Twenty-first Annual Report 
The epipodite is small and has no filaments. 
1. (Fig. 71.) The appendage is now more specialised. The proto- 
podite joints are no longer distinct, but fused. 
The epipodite is still small and without filaments. 
The branchia shows a little segmentation. 
The 5-jointed endopodite retains the character of the preceding 
stage, but its first and second joints have now a number of ciliated hairs. 
Enlarged drawings of two of the spines on the fourth and fifth joints 
are shown in Figs, 75 and 87. 
The exopodite is of three segments. The first is broader and bears 
on its outer edge an expanded plate-like ridge, the edge of which has a 
series of teeth. On its proximal part there are two short plumose 
hairs. Distal to these there are five curved teeth, three of which have 
little lateral teeth, while the remaining two are plain (Fig. 71, a). 
Opposite the upper part of the ridge there are two similar teeth. The 
third joint bears five plumose sete and a plain hair. 
TuirpD MAXILLIPEDE AND PEREIOPODS. 
The third maxillipede and the five pereiopods are not functional in 
the Zoéa stages; they are found in the I. Zoéa as buds, forming with 
the diminutive sternum region pertaining to them a hemispherical mass 
situated between the bases of the second pair of maxillipedes and the 
first abdominal segment. The mass lies as it were in a cup-shaped 
depression. It is seen in side view in Fig. 76, and in ventral 
view in Fig. 85. The sternal region is an oval plate or disc, and is 
surrounded on both sides by the closely-packed buds of the third 
maxillipedes and pereiopods. The sternum shows some indication of 
segmentation. 
The buds of the third maxillipede and _ pereiopods were shortly 
described by Spence Bate as follows (p. 593) :—“ Posterior to the last pair 
of members that I have described [maxillipedes], several sacs are visible. 
These evidently contain the germs of the five pairs of pereiopoda, or 
true ambulating legs, the most anterior of which I think I have been 
enabled to perceive lying folded within the sac, as shown in Plate XL., 
Fig. IO. Some of the small sac-buds probably are the germs of the 
future branchie, and it is not improbable that in the embryonic condition 
they fulfil the object of their design sufficiently well for so immature a 
creature.”* That respiration is carried on by the buds of the gills 
is not at all likely. 
In tracing the development of the branchi it will be shown that, 
during the present research, conditions were observed partly in agree- 
ment with the view expressed by Hansen regarding the connection 
between the limbs and the branchie. According to that author, the 
explanation of “the fact that in the Decapods branchiz are found upon 
the pleure, upon the arthrodial membrane between the pleure and the 
iimb, and also upon the coxopodite,” is to be found in the view that 
“the portion of the pleure provided with branchiz is to be regarded as 
originally belonging to the limb, so that we now find its vanished 
segment represented by branchiz alone.” 
TuirD MAxILLIPEDE, 3mp, Plates ix. and x. 
I. (Figs. 69, 76, and 85). The third maxillipede is a bifid bud; the 
branches are of unequal breadth; the narrower is the exopodite. On the | 
outer surface there are two swellings; the smaller, which is distal, is the 
* Op, cit. 
