Xe>'- GeriU8 of Terrestrial Isopoda. 17 



crossed by numerous ridges running parallel to one another and 

 transversely to the length of the mandible. Each ridge is 

 divided into a series of minute tubercles by transverse lines. 



The right mandible (Fig. 3) has a cutting edge unlike that of 

 P. australis and consists of two processes, the outer with four, the 

 inner with two projecting points, which are, however, not so 

 strongly chitinized as the corresponding structures of the left 

 mandible. The next process is somewhat narrower than that of 

 the left mandible, and its distal margin is crowned with a circle 

 of spiniform setae. The molar tubercle is longer and more slender 

 than the left one, the distal end is more obliquely truncate, and 

 the grinding surface, in minute structure, resembles that of the 

 left. The inner of the two cutting processes is united proximally 

 with the base of the setiferous process, and these two are capable 

 of slight movement on the basal portion of the appendage. 



The palp is three-jointed. The proximal part is the shortest; 

 the median is the longest and bears setae which are especially long 

 at the distal end. The third joint bears three long seta? at its 

 extremity. 



Loiver Lip (Fig. 4). — The lower lip consists of two fleshy 

 lobes united proximally. The distal end of each is rounded and 

 densely fringed with short setae which curve in towards the 

 middle line. These setae are carried on a series of processes of 

 the lobes and are thus collected into little brush-like groups. 



The median part, connecting the bases of the two free lobes, is 

 produced into the buccal cavity in the form of a grooved fold 

 fringed by setae. 



First Maxilla (Figs. 5, 5a). — Consists of two divisions, of 

 which the outer is the larger. It bends over somewhat towards 

 the middle line and its end is truncate and carries about twenty- 

 five strong brown chitinous teeth. The four outer ones are the 

 largest and are separated from the remainder, which are arranged 

 in three rows. The inner and the outer edges bear hair-like setae. 



The inner division is much smaller than the outer and forms 

 a narrow flattened plate pointed at its distal extremity, where 

 there is placed a group of setae, more numerous than those in 

 P. australis, and arranged in two series, an outer row formed of 

 stout, strong setae not more than one-third of the length of the 

 others and doubly pectinate at their distal ends, and an inner 

 group of long, strong, finely plumose setae. 2 



