478 



DECAPODA. 



pairs of antennae, mandibles, two pairs of maxillae, the second commencing 

 to be biramous, and a small stump representing the first pair of maxillipeds. 

 The part of the body bent over consists of a small quadrate caudal plate, 

 and an appendage-bearing region to which are attached anteriorly three 

 pairs of biramous appendages the second and third maxillipeds, and the 

 anterior pair of ambulatory legs and two pairs of undivided appendages 

 the second and third pairs of ambulatory legs. In a slightly later stage the 

 first pair of maxillae becomes biramous, as also does the first pair of maxilli- 

 peds in a very rudimentary fashion. The second and third pairs of ambu- 

 latory legs become biramous, while the second and third maxilliped nearly 

 completely lose their outer ramus. Very small rudiments of the two hinder 

 ambulatory legs become formed. If the embryo is taken at this stage (vide 

 fig. 222 A, which represents a nearly similar larva of Palinurus) out of the 

 egg, it is seen to consist of (i) an anterior enlargement with a vaulted dorsal 

 shield enclosing the yolk, two stalked eyes, and a median eye ; (2) a thoracic 

 region in which the indications of segmentation are visible with the two 



FIG. 222. LARV.* OF THE LORICATA. (After Claus.) 



A. Embryo of Palinurus shortly before hatching. 



B. Young Phyllosoma larva of Scyllarus, without the first maxilliped, the two 

 last thoracic appendages, or the abdominal appendages. 



C. Fully-grown Phyllosoma with all the Decapod appendages. 



at 1 , antenna of first pair ; at 3 , antenna of second pair ; md. mandible ; mx 1 . first 

 maxilla; mx*. second maxilla; mxp l mxf. maxillipeds; /* f 3 . thoracic 

 appendages. 



posterior pairs of maxillipeds (mxp* and mxf) and the ambulatory legs (p*)\ 

 (3) an abdominal region distinctly divided into segments and ending in a fork. 

 Before the embryo becomes hatched the first pair of maxillipeds becomes 

 reduced in size and finally vanishes. The second pair of maxillae becomes 

 reduced to simple stumps with a few bristles, the second pair of antennae 



