SCHIZOPOD FEOM TASMANIA. 289 



This appencla^^e lias a uniformly smooth margin, but it is slightly raised into a median 

 ridge, especially in its basal portion. The third joint, which is subequal with and 

 nearly covered by the scaphocerite, is slightly longer than broad, flattened and thickened 

 on each margin, where it bears a fringe of plumose setse, those on the inside being the 

 longest. The fourth joint is shorter and narrower than the third, and is also similarly 

 furnished with plumose setae ; at its exti-emity it bears a very short joint, which, 

 though somcAvhat narrower than the one bearing it, is considerably broader than the 

 joint of the flagellum which succeeds it. It is probably the fifth joint of the peduncle 

 Avhich is thus almost merged in the fourth. 



The flagellum is not quite tAvo-thirds as long as the body of the animal, and is 

 composed of very numerous (45 to 60) joints. Each joint bears at its extremity on both 

 sides a number of seta3, those at the proximal end being long and plumose, hut dimin- 

 ishing in size and becoming smootli on the more remote joints ; the last joint is blunt 

 and bears numerous short simple setoe. 



The oral aperture (PI. XXV. fig. 10) as seen from below is well defined. The dipper 

 lip is a thick fleshy appendage, rounded in front and widening out below. It seems 

 to have very considerable flexibility and power of movement, and is strongly supplied 

 with muscular bands. Close behind it lie the cutting-edges of the mandibles (PL XXIV. 

 figs. 10, 11, and 12), which are similar on both sides. These organs are strongly 

 developed, and are so placed as to close the mouth-opening with their exposed side. 

 The cutting-edge is furnished with a double row of strongly indurated teeth, while 

 placed nearly at right angles and interior to it is a ridge fringed with short bristles, 

 culminating in a strongly-produced grinding tubercle with an oval finely-toothed margin. 

 Tlie palp is 3-jointed, and when at rest projects forward between the bases of the first 

 pair of antennae : the basal joint is broader than long, and furnished with a few short 

 plumose setsB on each side ; the second joint is much the longest, is three or four times as 

 long as broad, and bears a tuft of setse at its upper distal extremity ; near its base on the 

 lower side it is produced into a short triangular tooth, while on the distal two-thirds of the 

 same side it hears numerous short setse arranged in two rows and leaving a long narrow 

 groove, into which apparently the third joint can be folded and so completely protected ; 

 the third joint is short, slightly broadened towards the outer end, and densely fringed with 

 short seta?. All the setse on this organ are furnished with very short hairs, which 

 almost make them appear serrated. The base of the mandible is widely dilated for the 

 reception of the powerful muscles by which it is moved. 



The under-lip (PL XXIV. fig. 9), placed immediately behind the mandibles, is a deeply 

 2-cleft fleshy plate, rounded on the outer margins, and finely fringed on the upper and 

 inner with minute close-set hairs. The two sides appear to be capable of opening widely 

 apart. 



First maxilUe (PL XXIV. fig. 6). — These organs are 2-branched; the external branch, 

 which is strongly chitinous, bears on its inner oblique margin a double row of serrated 

 spinose teeth, which are brown-coloured and strongly chitinized ; the inner branch is 

 Heshy, smaller, more rounded, fringed Avith sliort plumose setse, and seems to have but 

 little power of movement. 



