i6o 



CRUSTACEA EUCARIDA DECAPODA 



CHAP. 



behind is converted into the Trutozoaea (Fig. 107), possessing "two 

 pairs of biramous maxillipedes. It should be noted that the 

 maxillae, which are foliaceons in the adult, are laid down in this 



FIG. 107. -Protozaea larva of Pewews, sp. x 25. 



(From Balfour, after F. Mullrr. ) 



Mxp 



..- Ab.6 



, ... FIG. 108. Zoaea larva of Peneiis, 



condition in the larva, and this pnn- sp . x 25 . Aj A > t lst a mi 2ml 



ciple holds good throughout Cms- ""teimae ; Ab.G, 6th abdominal 



. appendage; 



tacean metamorphosis, VIZ. that when 



a limb is foliaceons in the adult it 



2nd maxilli- 



pede ; T, 4 th-8th thoracic append- 

 agea future walking legs). (After 

 F. Miiller.) 



is foliaceons in the larva, and when 

 hiranions in the adult it is biramous in the larva. Whilst the 

 rest of the thoracic limbs are still rudimentary, the sixth pair of 

 pleopods are being precociously developed (Fig. 108), being the 

 only precociously formed limbs in the Peneidea, though the abdo- 

 minal segments are fully marked off before the thoracic segments, 

 and so must be considered as precocious in development. When 



