148 



Part III. — Tiuenty-first Annual Report 



value to the two others. It appears rather to be a bundle of muscles 

 enclosed in a thin chitin. T have not satisfied myself that it is a true 

 joint and in the following description have neglected it. 



First Maxillipede, 1 mp, Plates viii. and ix. (Fig. 78). 



I. (Figs. 57, 76, and 85). The first maxillipede consists of a 2-iointed 

 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 setae. 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 + 2 + 2:2:2:1:2:14-4. 



II. (Fig. 51). With an increase in size little difierence 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 setae, the two new set£e having 

 been added one on each side and a little behind the original four. 



III. (Fig. 53). The principal change in this stage is the addition of 

 two more setae to the exopodite, making in all eight setae. Vide Fig. 52, 

 which shows the end of the exopodite, side view. 



In two Zoeae 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 setae. 



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 setae. In 

 Corystes (Gurney) the exopodite had in this stage twelve setae. 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). 



Megalops (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 Zoea. The second and third joints, if, represent 

 the single long second joint of the Zoea. 



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 setae, 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 setae. 



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. 



