826 THE YOTAGE OF H.M.S. CHALLENGER. 



Lower Antennse. — Glaud-cone not very prominent, third joint shorter than the fifth, 

 somewhat curved; fourth joint longer than fifth, with the lower part thickened, the 

 lower distal margin carrying setae and an oblique row of four strong slightly bent spines, 

 alternately long and short ; the fifth joint with the upper margin straight, the lower 

 apical oblique, armed like that of the preceding joint ; the flagellum two-jointed, the 

 first not longer and not a great deal broader than the longest of the spines on the apex 

 of the peduncle, the second joint much shorter, tipped with two cilia and the rudiment 

 of a thii'd joint. In a second specimen the flagellum was definitely three-jointed. 



Upper Lip. — The broad distally widened plate seems to be without cilia on the 

 foremost edge, which has a small incision on each side. 



Mandibles. — The part in front of the palp and molar tubercle presents the appear- 

 ance of a large, bent, blunt tooth ; the apical part of this is found to show a line 

 marking off" the cutting plate, which shows the traces of a tooth above and below with 

 a rounded edge between ; there is also a squared secondary plate, rather broader at the 

 base than at the distal edge ; it would be natural to expect to find this secondaiy plate 

 on the left mandible, but it certainly appears to me to be on the right mandible, and 

 tlie figure of the mandible containing it will be found on the right hand in the Plate, 

 although that on the left hand, both from the absence of a secondary plate and the 

 shape of the molar tubercle, looks far more like a right mandible. The preparatory 

 growth seen within the transparent skin shows on both mandibles an edging to the 

 cutting plate of numerous small teeth turned backwards, while the secondary plate 

 above mentioned shows a border cut into four teeth. The enlarged figure, m.A., is 

 from the second specimen already alluded to. The molar tvibercle is prominent and 

 powerful, but apparently set with but few teeth a.nd many cilia. The palp is very 

 slight in structure, fixed a little above the molar tubercle, the first joint as long as the 

 third or nearly so, the second only slightly longer than the third, and on one side in the 

 second specimen actually shorter; the third joint is apically tipped with two unequal setse. 



Lower Lip of delicate structure, the forward lobes very broadly rounded, with a 

 lozenge-shaped interval between them, which is to a great extent covered by the inner 

 lobes, also broadly rounded but not dehiscent ; the mandibular processes divergent, with 

 rounded ends. 



First MaxiUse. — Inner plate small, without setae on the narrow apex ; outer plate 

 having the truncate apical margin occupied by nine spines of no great stoutness, two 

 of them apically bifurcate ; the palp, reaching little beyond the outer plate, and nut 

 beyond its spines, consists of two joints, the second scarcely exceeding the first in length, 

 tipped with three or four setae. 



Second Maxillw. — The outer plate longer and broader than the inner, both with 

 slender spines on the rounded apices, the inner plate having also one or two on the 

 inner margin below the apex. 



