26 G. O. Sars. 



its outermost part a distinct articulation, each of the joints 

 carrying a natatory seta Between the insertion of the 

 antennulæ is a small semicircular area, within which the 

 simple eye, or ocellus, is now distinctly observed, and be- 

 hind this area a strongly prominent, flap-like prominence 

 occurs, representing the anterior lip. Behind it, on each 

 side, the bodies of the mandibles are seen, as also inside 

 them, 2 small juxtaposed lobes representing the posterior 

 lip. Then follow 3 pairs of successive bud-like limbs, 

 which may also be traced in the last Nauplian stage inside 

 the skin (see fig. 4), but which only in the present stage 

 have become freely exposed. These limbs, however, are 

 not yet functionally developed, and look merely like simple 

 quadrangular plates extending across the ventral face of 

 the body, and almost meeting in the middle, each plate 

 projecting at the inner posterior corner to a small rounded 

 prominence, which on the posterior pair appears double. 

 These plates are the first indications of the 2 pairs of 

 maxillæ and the maxillipeds. Behind them no trace of 

 others limbs are as yet to be detected, and, as the above- 

 named appendages are generally regarded as belonging 

 exclusively to the cephalon, by far the greater part of the body 

 is still represented only by that division. It may, moreover, 

 be demonstrated by the succeeding development, that the 

 short flattened projection extending behind these appendages 

 is chiefly transformed into the telson, whence it follows, that 

 the 2 body-divisions, mesosome and metasome, which in the 

 adult animal occupy by far the greater part of the body, are 

 as yet undeveloped. 



The body of the larva is still but slightly transparent, 

 and is to a great extent filled with indifferent cells, though 

 several of the internal organs may now be found to be. in 



