338 



DISCOVERY REPORTS 



and carries two membranous expansions, one distally a, the greater part of it lying on 

 the hinder end of the axis of the process, one b on the foremost side immediately near 

 the bend. The distal end of the former touches the latter. The foremost expansion b 

 is striated, that which is distal and for the most part hindermost a is not [A secondary 



Fig. 14. 



Fig- 15- 



Fig. 14. First pleopod. Development of the petasma. ■: 30. //, inner lobe; ml, middle lobe; pi, 

 lateral lobe; pp, proximal process; pt, terminal process; tv, wing. 



Fig. 15. First pleopod. Mature form. Left side, x 30. //, inner lobe; ml, middle lobe; pa, additional 

 process; pi, lateral lobe; pp, proximal process; pt, terminal process; si, setigerous lobe; w, wing. 



process] is present in the majority of males, though not in all, as a spine c bent forwards 

 over the foremost expansion b. It may be as long as that shown in Fig. 30, ^i, dz [my 

 Fig. 16] or very much smaller, or it may be entirely wanting: of thirty heavily chitinised 

 males examined, it was present in the left petasmas of twenty, absent from those of ten. 

 The lateral process pi is curved at the end ; it carries no tooth or secondary process. On 



