POST-LARVAL STAGES OF JASUS LALANDII. 



113 



unbranched limb, the distal end of which is chisel- or gouoe-shaped and lies 

 almost at right angles to the body, so that the outer edge alone is seen when 

 the animal is viewed from below (fig. 27, md.). At this outer edge the stout 

 tridentate spine, already noted in an earlier stage, may be seen ; it is followed 

 by two short, rather blunt and thick spines, after which a series of longer, 

 thinner, and sharper spines extending to beyond the middle of the mandible- 

 edge, which may be described as the cutting part. Here they abruptly cease, so 

 that it appeared at first as if they had been broken off, but this was observed 



Fig. 27. 



*.mx.1 



Mouth-parts of Pliyllosoma of 35 mm. 



also in other specimens and may be natural. The spines towards the middle 

 are somewhat hook-shaped. After the interval devoid of spines there is 

 another but smaller group of spines, close to the base of what may be termed 

 the molar part of the mandible (fig. 26, mol.). This last is a characteristic 

 cup or groove-shaped structure with projecting sides, forming a well-marked 

 concavity, in which are situated a number of closely-set short spines, the 

 whole forming a distinct projection which is reflected in the sub-cuticular 

 tissue. This projection is of importance, as, later on, it apparently forms 

 the flat molar surface of the adult mandible or part of it. 



The first maxilla (figs. 28, & 27, mx.V) is of interest chiefly in the appearance 

 for the first time of a trace of the endopodite, not previously recorded in any 

 pliyllosoma. It is in the form of a small projection at the base of what is 



