Descriptions of some Australian Phyllopoda. 21 



promineoce, within which the eyes are located. Above this 

 frontal prominence the dorsal face of the head is evenly con- 

 vex, and carries a peculiar claviform appendage, the affixing 

 organ, also met with in the genus Limnadia. Below, the 

 head forms a compressed, obtusely triangular expansion, the 

 rostrum, which turns straight downwards, and is defined from 

 the frontal part by an obtusangular notch. Of appendages, 

 the head carries the antennulæ and the antennæ, and is con- 

 tinued backwards, on the ventral side, to the anterior lip or 

 labrum. At the limit between the head and the cervical seg- 

 ment, occur on each side the powerful mandibles, and imme- 

 diately behind them, issue, from the ventral side of the cervi- 

 cal segment, the 2 pairs of maxillæ, no distinct posterior lip 

 being present. 



The part of the body extending behind the dorsal liga- 

 ment and the adductor muscle of the shell, is nearly cylindric 

 in form, though slightly tapering distally, and comprises the 

 mesosome, the meiasome and the urosome. The 2 former 

 divisions, however, are far from being distinctly defined, and 

 are both divided into a number of very uniform segments, 

 each of which carries ventrally a pair of branchical legs. The 

 total number of these pedigerous segments is 17, the 9 ante- 

 rior of which may perhaps be referred to the mesosome, the 

 remaining 8 to the metasome. The latter segments are pro- 

 vided dorsally with transverse rows of stiff bristles, which 

 gradually become transformed to short spines; the last seg- 

 ment is only defined in its ventral part. The urosome or tail 

 I'orms a short deflexed piece, the posterior part of which is 

 composed of 2 juxtaposed lamellæ dentated at the edge. At 

 its tip are articulated the caudal claws, and from a small 

 tubercle on the dorsal side issue the 2 caudal setæ. 



Within the body may be faintly traced the intestinal tube, 

 \vhich debouches at the tip of the tail, between the caudal 

 claws, and anteriorly is provided witli 2 richly ramified cæcal 



