454 



THE VOYAGE OF H.M,S. CHALLENGER. 



integument of the carapace. 



- mdb 



The carapace is longer, narrower and more rectangular in a 

 dorsal view than it was at the last stage, 

 and it makes only about one-third of the 

 total length of the body. 



Up to this time, Professor Brooks 

 says the mode of motion has been short, 

 jerking Nauplius-like leaps, and the two 

 pairs of antennae have been, as they were 

 when the larva left the egg, the chief 

 organs of locomotion. The structure of 

 these appendages has remained extremely 

 constant through all the moults, but they 

 now entirely change their character and 

 lose their locomotive function. 



The change which is undergone by the 

 larva at the end of the Zoea series is very 

 much greater than at any preceding moult, 

 except that between the Nauplius and the 

 first Protozoea, and in some respects it is 

 even greater than it was at that time. 

 After the moult it is about T ^^j of an 

 inch (or l - 75 mm.) long, with seven pairs 

 of long-jointed, biramose, swimmiug feet, 

 fringed with long slender hairs. The 

 swimmerets are also present as functional 

 appendages with long fringing hairs. 1 



Professor Brooks' figure was drawn 

 from a Zoea which was captured at the 

 surface of the ocean, carefully examined, 

 and compared with one previously ex- 

 amined (loc. cit., fig. 43), and found to 

 agree with it exactly. It was then placed 

 alone in a smab 1 beaker of sea-water. 

 The next day it was found to be moult- 

 ing, and a drawing was made from it 



Fig. 56. — Lucifer in tie Acanthosoma stage, from a drawing by 

 Willemoes S'uhm. a 1 , first antenna ; a-, second antenna ; I, labruin ; 

 mdb, mandibles; mx 1 , first maxilla; ma; 2 , second maxilla; mxp, 

 maxilliped ; g\ first gnathopod ; g, second gnathopod ; p 1 ' 4 , 

 pereiopoda. 



1 It should be here noticed that by swimmerets and 

 swimming feet Professor Brooks does not mean the 

 pleopoda that are so named in Crustacea generally, but 

 the immature pereiopoda and their accompanying 

 branches. 



