148 Part IT —Twenty-first Annual Report 
value to the two others. It appears rather to be a bundle of muscles 
enclosed in a thin chitin. I have not satisfied myself that it is a true 
joint and in the following description have neglected it. 
First MAXILLIPEDE, | mp, Plates viii. and ix, (Fig. 78). 
I, (Figs. 57, 76, and 85). The first maxillipede consists of a 2-jointed 
protopodite. The first is short, the second is a long joint. To the 
latter are attached the endopodite and the exopodite. 
The exopodite is a 2-jointed branch bearing four long densely 
plumose sete. Two of these are terminal, and two arise, one on each 
side, a little behind the former. 
The endopodite is 5-jointed, and is furnished with a number of long 
serrated hairs. On the end joint (Fig. 78) there are four serrated hairs 
and a short smooth hair. On the second joint there are two of the 
former, on the third joint one, and on the second and first, two hairs 
each. 
The protopodite has a number of smooth hairs. Two arise from its 
inner edge close to the base of the endopodite. Six more are found on 
other parts of the inner edge. The formula of the arrangement of hairs 
on the protopodite and endopodite was, 0: 4 + 24+ 2:2:2:1:2:1+44. 
II. (Fig. 51). With an increase in size little difference is found in 
this stage. 
There is an extra hair on the second joint of the protopodite, and 
certain of the hairs on it have a few short cilia. 
The exopodite has now six plumose sete, the two new sete having 
been added one on each side and a little behind the original four. 
ITT. (Fig. 58), The principal change in this stage is the addition of 
two more setz to the exopodite, making in all eight sete. Vide Fig. 52, 
which shows the end of the exopodite, side view. 
In two Zoée which from the stage of development of the pereiopods 
and -pleopods evidently belonged to this stage, viz. the III., the exopo- 
dites of the first and second maxillipedes had six swimming setee. 
On the first joint of the protopodite in this stage a small process was 
seen which is the epipodite (ep). 
IV. (Fig. 41). The exopodite has now ten swimming sete. In 
Corystes (Gurney) the exopodite had in this stage twelve sete. An 
additional spine was found on the last joint of the endopodite. 
The hair formula was, 0: 6 + 2:2: 2:1:2:4. 
The epipodite (ep') is now large and prominent (Fig. 67). 
Meceatops (Figs. 43 and 49), The first maxillipede now approaches 
the adult condition. 
‘The protopodite is 3-jointed. ‘The first joint bears the epipodite; it is 
the first joint in the Zoéa. The second and third joints, W/, represent 
the single long second joint of the Zoéa. 
The endopodite is a 1-jointed hammer-shaped flattened process, 
bearing on its upper edge three short smooth hairs. 
The exopodite is 2-jointed, and is bent at a right angle. On the 
distal end of the first joint it has usually two plumose sete, sometimes, 
as in the example drawn, one only. The second joint shows a line 
crossing it obliquely, which indicates a rudimentary joint. It bears 
four plumose setz. 
The second and third protopodite joints are furnished along their 
inner edges with a number of hairs, some of which are ciliated (Fig. 49). 
The epipodite, which is a process of the first joint, bears eight long 
thin slightly curved hairs. They are stiff, and are found mainly on the 
outer edge. On the “heel” of the epipodite is a pair of smooth hairs. 
