510 



CRUSTACEA MALACOSTBACA. 



At what is known as the Erichthus 

 stage of this larva (Fig. 312), which 

 follows the Erichthoidina, all the ab- 

 dominal appendages are developed and 

 the two anterior pairs of thoracic legs 

 are much elongated. The three suc- 

 ceeding legs have dwindled to an almost 

 vestigial condition, and it is not until 

 the later period of larval life that they 

 elongate and acquire their chelate 

 extremities. The rudiments of the 

 6th-8th thoracic legs have now ap- 

 peared. 



In Squilla the eggs hatch as Alima 

 larvae at a stage of development corre- 

 sponding to the Erichthus stage above 

 described. The body is however more 

 slender in proportion to the size of the 

 carapace, the shape of the latter and of 

 the telson is different, the cephalic 

 region is much elongated, and the six 



A 



FIG 312. Older Erichthus larva 

 (from Korschelt and Heider, 

 after Claus). a', a" first and 

 second antennae ; I-V maxilli- 

 peds ; VI- VIII rudiments of 

 the posterior thoracic legs ; 

 ai-a 5 pleopoda , br branchial 

 rudiments. 



posterior thoracic legs are 

 entirely absent (Fig. 313). 

 The stage in the life- 

 history of Stomatopods 

 in which the first and 

 second thoracic limbs are 

 well developed while the 

 remaining thoracic limbs 

 are reduced (Erichthus) 



FIG. 313. Young Alima larva (from Claus). 

 Af abdominal feet (pleopods) ; Mxf anterior 

 maxillipeds ; Mxf the large maxillipeds 

 (second pair). 



