ORAL APPENDAGES OF MARINE ISOPODA. 75 



and seven long spines respectively, most of these are serrated : the inner- 

 most lobe has sixteen to twenty setose spines, varying in size, the last one 

 on the inner margin being the longest. 



The Maxillipede (Pi. 7. fig. 5). — In this species this appendage is com- 

 paratively small, but of a very robust type and having its margins densely 

 fringed with setse and spines. The inner division of the coxopodite is small, 

 almost cuboid. The basipodile is also very small, measuring only about half 

 the length of the palp. Its anterior and posterior margins are obliquely cut 

 away, sloping towards the outer margin : the inner margin is fringed with 

 fine, closely-set setse. The five-jointed palp has the first joint rather larger 

 than in most species, the second joint is comparatively small, the third the 

 largest and with a lobe-like extension on the inner side, the fourth joint is 

 longer than the third, but much narrower, whilst terminally there is a small 

 fifth joint. All the joints are fringed with setae, which are extra long on the 

 fifth joint. The inner distal lobe extends to the anterior border of the second 

 joint of the palp and is fringed with setose spines terminally. The epipodite 

 is almost circular and extends as far as the middle of the second joint of the 

 palp. It is fringed with short, closely-set setae. 



Pentidotea, Richardson. 



5. Pentidotea hesecata (Stimpson). (Pi. 7. figs. 6, 7.) 



Idotea resecata, Stinipson, Bost. Journ. Nat. Hist. vol. vi. (1857) p. 504, pi. 22. fiy. 7 ; 



Miers, Journ. Linn. Soc, Zool. vol. xvi. (1881) p. 45. 

 Pentidotea resecata, Richardson, Bull. No. 54, U.S. Nat, Mus. 1905, p. 369, iigs. 400, 401. 



The First Maxilla (PI. 7- tig. &). — This appendage in this species has not 

 previously been figured or described. The outer lobe terminates in twelve 

 spines, the innermost five of which are denticulate; there is a long fine spine 

 about the middle and then six stout curved spines on the outer side. The 

 inner lobe terminates in three long setose spines and a setule on the outer 

 anterior margin. 



The Maxillipede (PI. 7- fig. 7). — This appendage is greatly elongated in 

 this genus and characterized by the large epipodite. Miss Richardson has 

 given a figure of the maxillipede, but it is inaccurate in detail. The basi- 

 podite is narrow and greatly elongated and has straight inner, outer, and 

 posterior margins. It is longer than the palp, which is five-jointed, the 

 terminal joint being quite small. The inner distal lobe is narrow and 

 the spines on its terminal margin setose. The epipodite is a large, elon- 

 gated, wide plate extending forward as far as the middle of the third joint 

 of the palp. It is slightly narrower anteriorly than posteriorly, but wider 

 throughout than the basipodite. 



