NAUPLIOID STAGE IN PALINURUS. 229 



The first maxilla is well developed and shows active movement. It is 

 unsegmented, but biramose, each of the short stout branches being turned 

 inwards and terminated by two or three long sharp spines as yet covered by 

 cuticle and apparently not functional. 



The second maxillw lie at some distance from the first maxillse and other 

 mouth-parts. They are comparatively well developed, but unsegmented, 

 being long blade-like organs projecting forward from their points of attach- 

 ment on the body. Their outer margins are straight, while their inner is 

 convex, and shows no lobes, though provided with a spine. Their greatest 

 breadth is about one-third of their length. At the free extremity of this 

 appendage are three long spines, not easily made out as they are still covered 

 by cuticle. 



The: first maxilliped appears as a minute knob or projection of the body, 

 about one-quarter of the breadth of the first joint of the succeeding appendage 

 in breadth, and not much over this in length. It is terminated by a sharp 

 spine about its own length. It is situated about midway between the 

 neighbouring appendages and towards the middle line of the body, so that 

 its free end scarcely reaches the margin of the body. It is thus a mere 

 rudiment. 



The second maxilliped is much longer, and extends forward in a curve to 

 about the middle of the cephalic region. It consists of five distinct segments 

 terminated by spines still in cuticle. It is not provided with an exopodite. 



The third maxilliped is similar to the second^ but is longer. Both are, at 

 this stage, folded inwards under the three succeeding walking-legs. There 

 is no exopodite. 



^\ie first and second walking-legs are much stouter, being about twice the 

 breadth of the preceding appendage at their bases. They are much shorter 

 than in the next stage, being compressed within the cuticle so that they 

 appear twisted or folded on themselves, a condition specially marked in the 

 third joint of the endopodite. The exopodite is not folded and is not as 

 yet provided with the swimming-setas so characteristic of their condiiion 

 in the next stage, though these may be seen indistinctly under the cuticle as 

 well as the segmentation of this appendage. The two powerful muscles with 

 which it is provided for swimming purposes at the next stage are distinctly 

 visible. 



The third walking-leg differs from the first and second, and though long and 

 folded on itself like them, has only the rudiment of an exopodite. 



The fourth loalking-leg is scarcely to be distinguished as a small swelling, 

 while the fifth is not present even in rudiment. 



In comparing this larva with that of other known larvse of the Loricata 

 we notice some striking differences. The European Palinurus and Seyllarus 

 have been investigated by Dohrn (1), Clans (2), and Richters (3), and their 



