458 



TRANSFORMATIONS OF INSECTS. 



the anterior are simple, and the other two branched (biramose). 

 These Nauplii have no carapace, no paired eyes, no masticating 

 organs, and the mouth is over-arched by a helmet-hke hood. 



This rudimentary larva or Natiplms soon alters in shape, moults, 

 and a fold of skin grows across the back behind the third pair of 

 feet, and four pairs of stout processes (rudiments of new limbs) 

 sprout forth on the ventral surface. Within the third pair of feet 

 powerful mandibles are developed. In a subsequent moult the new 



YOUNGEST NAUPLIUS OF A PRAWN. 

 Magnified 25 diameters (after F. Miiller). 



limbs (maxillae and antennae and intermediate maxilipedes — foot 

 jaws) come into action, and the Naupliiis becomes a Zoca, agreeing 

 perfectly with the Zoea of the crabs in the number of the appendages 

 of the body, although very different in form and mode of locomo- 

 tion, and even in many particulars of internal structure. The 

 chief organs of motion are still the two anterior pairs of feet 

 which are slender, and furnished with long setai or hair-like spines. 

 The third pair of feet loses its branches, and becomes converted 

 into mandibles destitute of palpi. 



The labrum acquires a spine directed forwards, and of consider- 

 able size, and the two-branched foot jaws appear to assist but 



