102 dr. j. d. f. gilchrist on lakval and 



The Naupliosoma. 



For comparison with later stages, further details with figures, of the 

 appendages, may be given. (I may here note incidentally that the name 

 suo-o-ested as convenient to denote this stage was not intended to suggest any 

 connexion with the nauplius stage, which, as stated, has presumably been 

 passed long before in the development of the embryo. The name was given 

 on account of the apparent resemblance of this stage, when seen in the living 

 condition, to a nauplius ; it was not intended to suggest any direct relation 

 -to the nauplius stage, and, in so far as it does so, is inappropriate.) 



The antennules (PL 13. fig. 1) are as described, and it may be added that, 

 in addition to the stout terminal spines under the cuticle, the long filamentous 

 processes, described in the next stage, can also be made out, though not 

 clearly, as they are coiled up under the cuticle. 



The antennce (PI. 13. fig. 2) are also as described. The protuberances at 

 their bases seem, on further examination, to be due to the presence of the 

 antennal gland. 



The mandibles (PI. 13. fig. 3), as viewed from below, are short limbs, bent 

 inwards at their tips, which end in a tridentate spine. When they are 

 dissected out and viewed from the posterior or anterior aspect, the spine is 

 seen to be the first of a series, which extends inwards towards the body and 

 ends in a separate group of small stout spines. The whole is covered by 

 cuticle, and as the general arrangement of these spines does not differ 

 essentially from that in the largest phyllosomas, they will be described there 

 in more detail. 



The first (PI. 13. fig. 4) and second maxillce (fig. 5) are as described. 



The rudimentary /irsii maxillipede (fig. 6) does not appear to have a cuticle 

 covering its single spine at this stage. 



The second maaillipede (fig. 7) consists of five distinct segments : the first 

 is short and is followed by a long one; the third is again short, the fourth is 

 longer, and the fifth is small and terminated by about four spines under the 

 cuticle. 



The third maxillipede (fig. 8) has also five distinct segments, the first 

 short, the second very long, and, at its proximal end, coiled or folded on 

 itself, there being about two such distinct coils or folds ; the third segment 

 is short, straight and not coiled, as are also the fourth and fifth, the last 

 having some spines under the cuticle. The whole appendage is bent in the 

 form of an irregular S, and, in its normal position lies, compactly folded up, 

 under the succeeding appendages, which are arched forward over the ventral 

 side of the body. 



The first pereiopod (fig. 9) has the first two segments broad, comparatively 

 short, and well provided with muscles ; the strong spine, so well developed 

 in the phyllosoma on the first segment, does not appear. In the second the 



