MOUTH-PARTS OF THE PALuEMONID PRAWNS. 



59 



have fused with one of the adjoining segments. The mandibular 

 palp represents the remainder of the axis of the limb. Its first 

 segment is undoubtedly the basipodite, though there is nothing 

 to show whether it is a 'complete symbasipodite. Often a joint 

 divides the remainder into two parts, but these cannot be regarded 

 as corresponding with any of the normal segments of the 

 endopodite *. 



The mandible of the Crustacea is an exceedingly complicated, 

 varied, and interesting organ, presenting many problems and 

 worthy of a great deal more attention than it has received. 



Text-figure 37. Text- figure 39. 



Text-figure 38. 



Text-fig. 37. Left mandible of Leander serratus. 



„ 38. End view of molar process of the same limb. 

 „ 39. End view of right mandible of Leander serratus. 

 For lettering see p. 71. 



The lacinise of the malacostracan maxillule (text-fig. 46) repre- 

 sent the first and third endites. This is suggested, though hardly 

 proved, by the condition of the limb in Nebalia. Hansen has 

 shown that in various other genera the lacinise belong to the first 



* G. W. Smith (Q. J. M. S. liii., iii. p. 506, 1909) describes a mandibular palp 

 in Parana slides which would be quite unique among such structures in the 

 Malacostraca, having four joints and an exopodite. I am unable to confirm this. 

 All the specimens in the British Museum have three joints and no trace of 

 exopodite. 



