14 PEOF. M. M. HAETOG ON THE 



(posterior) edge arched, inner concave up to the false articulation, below which it bears 

 a stumpy 2)alj)ifo7'm process, with two setose plumes ; above bearing a tapering setose 

 plume, and then trending obliquely back to the end of the joint. Posterior edge of 

 base prolonged obliquely inwards and forwards towards the opposite side into a foot-like 

 proper apodeme. The nephridium opens near the base of this joint on its posterior inner 

 face. 



Second joint developed only on the anterior inner edge and, as it were, let in between 

 the first and third ; j)rolonged inwards like a sort of finger, bearing a terminal strong 

 spine twice its length, fringed with a few coarse setae, and a much shorter spine, curved, 

 and lying on the distal edge of the former. 



Third joint flattened, oblong, bent inwards at an obtuse angle, the first produced at 

 its inner anterior edge into a process ending in a falciform spine, bearing on its con- 

 cave (upper) edge, a little below its end, a row of setiform teeth ending in a larger one ; 

 facing the concavity of the spine is jointed another, tapering and pinnate, with coarse 

 setae in its lowest two thirds, and just at the junction of the two, on the inner side, is a 

 fine hair. 



Fourth joint inserted just at the base of the introrse process of the last ; it is squarish, 

 and bears at its distal end, on the inner side, a fine cm'ved hair, a strong, smooth, 

 somewhat falciform acute spine, fringed on its concavity, near the base, with a few setse. 



Fifth joint a mere knob at the end of the last, but, as we shall see, with distinct 

 extensor and flexor muscles of its own ; it bears two strong falciform spines, toothed on 

 the concave upper side {i. e. towards the body). The several spines being all on the 

 anterior inner side, and capable of apjiroximation by the muscles acting on the joints 

 that bear them, convert the limb into a prehensile member, justly termed " hand " by 

 Jurine. 



Froper Muscles of the Outer Maxilliped. — Extensor of the false joint originating on 

 the carapace (with the extensor abductor of the limb external to which it lies), inserted 

 into the limb on its extensor side, just beyond the false joint. 



Muscles of the palpiform jyrocess : extensor from proper apodeme, flexor from top of 

 carapace (internal to extensor abductor). 



Muscles of second joint : flexor from post-maxillary apodeme, extensor from proper 

 apodeme ; these muscles run near the flexor side of the limb. 



Muscles of third joint : extensor and flexor ; strong-bellied muscles from proper 

 apodeme to inner and outer proximal margins of third joint. 



Muscles of fourth joint: extensor and flexor; two strong slips from base of third to 

 base of fourth joint. 



Muscles of ffth joint: extensor and flexor; two small slips from same origin as last 

 two, and running between them and through fourth joint to base of fifth. 



Extrinsic Muscles of Outer Maxilliped. — Long flexor-adductor. A broad fan-shaped 

 muscle, converging upwards from sides of carapace to upper side of basal apodeme. 



Second and Third jlexor-adductors, from free entosternite and intermaxillary septum 

 respectively to proper apodeme. 



