REPRODUCTION 



275 



blastodermic cuticle; when ripe it emerges in the condition 

 known as the " Trilobite-larva " (Fig. 158), so called iVom a 

 superficial and misleading resemblance to a Trilobite. They 

 are active little larvae, burrowing in the sand like their parents, 

 and swimming vigorously about by aid of their leaf-like posterior 

 limbs. Sometimes they are taken in tow-nets. After the first 

 moult the segments of the meso- and meta-soma, which at first 

 had been free, showing affinities with Prestwichia and 7,V//// /////* 

 of Palaeozoic times, become more solidified, while the post -anal 

 tail-spine absent in the Trilobite larva makes its first 



1 



V 



Fie:. 158. Dorsal and ventral view of the last larval stage (the so-called Trilobitr s1 



of Li ni a I a. \ jinlii/ilii'iiius before the a]ipeaniiK-e of the tdson. 1, Liver: '2, im-diaii 

 eye; 3, lateral eye ; 4, last walking leg ; 5, rliilaria. (From Kin'j^li-\ ;nnl '[' :ikan<>. 



a)ipearance. This increases in size with successive nmnlts. \\<> 

 have already noted the late appearance of the external sexual 



characters, the chelate walking appendages only bring r< placed 

 by 1 looks at the last moult. 



Lirnulus casts its cuticle several times during the l\\^\ yeai 

 Lockwood estimates five or six times liet \\een hatching out in 

 I une and the onset of the cold weather. The cuticle splits alon- 

 a "thin narrow rim" which "runs mum! the under >\<\r of the 

 anterior portion of the cephalic shield." This extends i:nlil it 

 reaches that level where the animal is widest. Through this slit 

 the body of the king-crab emerges, coming out, not as that o|' a 

 beetle anteriorly and dorsal ly, but anteriorly and \entrally. in 



1 Lockwood, Amer. -W. iv., 1870-71, [*. 



