498 O. W. HYMAN 



The antennules and antennae show only sHght changes. The 

 mandible and first maxilla are very slightly altered also, but the 

 second maxilla (fig. 61) is changed both in shape and in the rela- 

 tive size of its parts. The scaphognathite has increased in size; 

 the two basal lobes are larger and are partly constricted from the 

 coxal segment ; the palp is relatively smaller and is reduced to an 

 inconspicuous lobe of the lateral basal lobe. 



The maxillipeds (figs. 69, 71, and 75) show changes, but none 

 so marked as in the previous molt. In the first, the change is 

 largely an increase in size and apparent strength. The endopo- 

 dite has changed shape and is now a trisegmented, flattened ap- 

 pendage with the middle segment twisted or folded on itself. 

 All its segments are hairy. The basipodite and coxopodite ap- 

 pear as prominent rounded lobes medially, but fuse into an un- 

 jointed mass laterally. Each lobe has a spiny border. The 

 epipodite is larger and bears scattered, slender, barbed hairs. 

 The second maxilliped is not greatly changed. The proximal 

 segment of the endopodite is relatively larger and bears a row of 

 stout spines along its median border. The tubercle of the future 

 gill and epipodite shows a differentiation into minute lobes. The 

 change in the third maxilliped is largely confined to the endopo- 

 dite, which is relatively larger, due to an increase in size of the 

 proximal two segments. The number of hairs is increased on all 

 segments, but especially on the lateral portions of the protopodite 

 and the proximal half of the epipodite. 



The chelae are further developed. Both the carpus and the 

 dactyl end in rounded, spoon-shaped points. Both chelae are 

 identical. The fifth periopods are adapted for walking and cling- 

 ing. They are small, but have the usual five segments of the 

 periopods. 



The most striking change among the appendages occurs in the 

 pleopods. These are no longer the well-formed, powerful swim- 

 ming organs of the megalops, but are smaller, hairless, and 

 shriveled. They are hidden between the abdomen and the 

 thorax. 



The second crab stage (fig. 17). After the next molt the crab 

 has increased in size from 1.35 mm. long and 1.25 mm. broad to 



