C. E. Beech er — Thoracic Legs of Triarthrus. 



469 



either branch. The posterior edge is finely denticulate, and 

 carries a row of long setae. The distal portion (1) is multiar- 

 ticulate, being composed of ten or more joints. In general 

 form, it is slightly crescentic, with the margins thickened, the 

 anterior one, being strongly crenulated. Long setae extend 

 posteriorly from the crenulations on the dorsal side of the leg, 

 making a conspicuous fringe along the distal half of the 

 exopodite. 



Figure 1.— Triarthrus Becki Green; dorsal view; showing antennas and paired 

 crawling and swimming thoracic legs x 3. (The antenna? and legs 

 on right side are from one specimen x 3, and the legs of the right 

 side are drawn from a smaller individual x 6). 



Figure 2. — Triarthrus Becki Green; dorsal view of right legs of second and 

 third free thoracic segmeats. x 12. 



Figure 3. — The same, with setae omitted from II, to show details of structure 

 ex, exopodite ; en, endopodite. The seta? are represented on III. x 12 



Figure 1 represents a dorsal view of Triarthrus Becki, 

 showing the antennae and the exposed portions of the append- 

 ages. The antennae and legs on the right side are drawn from 

 one specimen, and the legs on the left side are as shown in 



