REPORT ON THE CRUSTACEA MACRURA. 183 



pollex longer, and the apices pass more conspicuously beyond each other when closed. 

 The carpos is armed above and below with a long, slightly bent tooth ; so also is the 

 meros, which has also two smaller ones on the upper margin. 



The second pah- of pereiopoda is long, slender, and feeble, and terminates in a small 

 chelate extremity, of which the carpos and propodos are subequally long and wide, 

 having the upper and lower margins parallel throughout ; the dactylos is short, bends 

 upon, and when closed impinges against the pollex, or digital prolongation of the pro- 

 podos, throughout their entire length. 



The two posterior pairs of pereiopoda are subequally long, and terminate in long 

 styliform dactyli. 



The branchial arrangement appears to be similar to that of Nephropsis rosea, and 

 may be thus tabulated : — 



Pleurobranchiae, 



Arthrobranckiae, 



Podobranckia?, 



Mastigobranckiae, . 1 



The first pair of pleopoda is short and rudimentary, but I am not sure whether this 

 be the permanent state, or only an immature sexual condition, as I have failed to 

 determine whether the specimen be a male or a female. I closely examined the coxae of 

 the third and fifth pairs of pereiopoda, but failed to find a foramen in either. The central 

 position of the rudimentary first pair of pleopoda, together with the occurrence of 

 cincinnuli or small booklets attached to the long stylus of the second and succeed- 

 ing pairs of pleopoda, the narrowness of the ventral surface of the pereion, and the 

 large diameter of the primary branch of the flagella of the first antennae, without being 

 conclusive, suggest its being a male. 



The sixth or posterior pan' of pleopoda (PI. XXIV. fig. 2z) are broad and foliaceous 

 plates, the outer being armed with a short strong tooth at about half the distance between 

 the base and the distal extremity of the terminal margin, but having no distinct diaeresis 

 or joint dividing the plate. The inner plate is likewise armed with a sharp tooth, longer 

 than that on the outer plate, and nearer the extremity of the terminal margin, which in 

 both plates is furnished with a fringe of long simple hairs. 



The telson is long and quadrate, the sides slightly waved and reversely conformable ; 

 the posterior margin is rounded and fringed with long, simple hairs, and is separated 

 from the lateral margins by a strong, sharp tooth. 



