158 



ination. Each lobe is somewkat oblong in shape with the distal 

 angles rounded off and densely fringecl with setae, all more or less 

 directed inwards towards the median line. 



The Ji7-st maxilla (Plate xxiii., fig. 7) consists of two parts, the 

 outer part is longer and broader tlian the inner, its total length is 

 nearly four times the greatest bi'eadth, the outer edge is curved so 

 that the distal half is directed somewhat inwards to the median line. 

 On the end it bears about 10 to 12 short stout spiniform seta^ 

 arranged mainly in two rows, the outer seta^ are the largest, the 

 others decreasing in size inwards, some of the smaller are minutely 

 denticulated on the inner side near the middle. Both the inner 

 and outer margins of the outer portion of the maxilla bear a 

 number of very tine hairs, and near the inner distal angle one or 

 two delicately plumose setas arise a little below the base of the 

 spiniform teeth. 



The inner portion of the maxilla is oidy about half as long as 

 the outei*, and it is also narrower. It curves somewhat inwards 

 and bears fine hairs on both margins. The extremity bears four 

 or five large seta? somewhat distant from one another, each being 

 densely but finely plumose in the distal half. In addition to these 

 there are also two simple setre at the base of the plumose setse, 

 one at the outer distal angle, and the other at the centre of the 

 surface of the joint. 



In describing the first maxilla of lauthe speciosa, Bovallius 

 speaks of the two portions similar to those just described, as the 

 exapodife and rndopodife respectively.* The appendage is un- 

 doubtedly difficult of interpretation, but from Boas's comparative 

 i-esearches it appears more probable that these two portions repre- 

 sent the internal and external laciiiw arising from the basos and 

 ischios respectively, the remainder of the typical limb being lost.f 



The second maxilla (Plate xxiv.,fig. 1) consists of a basal portion 

 prolonged at its inner distal angle into a long rounded lobe, and 

 two lobes external to this articulating with the basal portion. 

 The inner margin of the ba.se is very slightly concave, and is sup- 

 plied throughout its whole length with a thick fringe of long setie, 

 these set* are arranged in a distinct line which at t!ie end leaves 

 the margin and is continued for a short distance along the surface 

 of the inner fixed lobe. The rounded end of the lobe is also fringed 

 with sette, the innermost of which are pectinated, while those in 

 the row along the inner margin are simple. 



The two articulated lobes are of about the same size, sub-oblong 

 in outline, curving slightly inwards and with the ends obliquely 



* " lanthc, a new genus of Isopoda," Bihnng. Till. K. Svenska "Vet. 

 Aka<l. Handlingar. Band 6, No. 4. p. 7- 



t See Parker — " The skeleton of the New Zealand Crayfishes." (Studif-s 

 in Biology for New Zeahmd Students, No. 4) p. 21 ; also Boas — " Studieu 

 ilbjr die VerwaudtsuhafLsbeziehuugen der Malakostraken. " 



