THE STOMATOPODA 



327 



form. The third, fourth, and fifth pairs undergo retrograde changes, 

 losing their exopodites and remaining for some time as shapeless 

 stumps, only later to resume their course of development into 

 chelate limbs. It does not seem to be the case, however, as is 

 sometimes stated, that they actually disappear. The last three 



A 



FIG. 191. 



Consecutive stages of a lan-a of the first Erichthvs-type. (According to Hansen, the larva 

 represented in C and D belongs to a different species from those shown in A and B.) c', 

 antennule; a", antenna ; oi, first pleopod ; a$, uropod ; I-V, first five thoracic ap]>endages ; 6-8, 

 last three thoracic somites. (After Glaus, from Korschelt and Heider's Einbryology.) 



thoracic somites remain for a long time devoid of appendages, and 

 it is only at a late stage, when the appendages in front and behind 

 are well developed, that rudiments of appendages begin to appear 

 on them (Fig. 192). The adult form is only assumed after a 

 considerable size has been reached, the carapace diminishing in 

 size, becoming coalesced with the anterior thoracic somites, and 



