960 THE VOYAGE OF H.M.S. CHALLENGER. 



third joint very short and (especially at the centre) narrow ; there is a calceolus at the 

 end of this, and two near the end of the preceding joint ; flagellum stout, with forty-six 

 joints, the first as long as five or six of the following, with three calceoli, the following 

 joints having each one, till near the end, cylinders on several of the distal joints. 



Lower Antennae,. — The basal portion of the composite first and second joints not 

 much expanded below, the distal part concave above, with a small, not prominent, gland- 

 cone below ; the third joint short, with long, fine, feathered setae at the apex ; the fourth 

 elongate, with distally feathered seta? and slender spines in groups along its inner 

 margin ; the fifth joint elongate, but shorter and much narrower than the fourth, with 

 ten calceoli along it, and setae as on the other joint ; the flagellum slender, of about 

 thirty-five joints, with calceoli on those of the upper half. The calceoli are large and 

 striking, especially in the middle part of the flagellum of the upper antennae ; a short 

 broad stalk supports an unusually large circular cup with radiate markings, from the 

 centre of which, and connected with it at the back, rises the usual oval piece shaped like 

 the bowl of a spoon, crossed by concentric lines, which are in this species very strongly 

 marked. 



Up>per Lip. — The outer plate broadly rounded, the prominent convex central part of 

 the distal margin fringed with small hairs and prickles ; the sides, which are also convex, 

 but somewhat drawn back from the centre, are as it were whiskered with long cilia 

 directed towards the centre, an arched row of such cilia crossing the whole breadth of the 

 plate. 



Mandibles. — The cutting edge long, incurved, much down-drawn, ending below in 

 two or three strong teeth ; the secondary plate on the left mandible strong, bent so as to 

 follow the curve of the principal plate, its long border divided into some eight strong- 

 teeth ; the secondary plate on the right mandible small, narrow, with a long apical tooth 

 below and one or more short ones above ; the spine-row on the left mandible consisting 

 of eight long spines with some cilia attending them ; on the right mandible the spines in 

 the spine-row appear to be fewer ; the molar tubercle prominent, the roughly-oval dentate 

 crown (as seen in the left mandible) set with some two dozen rows of denticles, and 

 carrying a small plumose seta at the upper corner ; there is a process between the molar 

 tubercle and the palp ; the first joint of the palp is concave on the inner side, the second 

 joint long, abruptly narrowed on the inner side about midway, furnished with numerous 

 setae of different lengths, more or less feathered, along the inner margin, and a row which 

 have their origin on the surface extending over more than the upper half; the third 

 joint rather longer than the second, crowded with spines of different lengths, the longer 

 ones pectinate, the longest at the apex differing from the others in having the apical third 

 unpectinate. 



Lower Lip. — The forward lobes, both inner and outer, rounded, rather strongly 

 ciliated ; the mandibular processes short. 



