PHOTIDAE 



227 



Gnathopod 1, 6th joint subcircular, shorter than 5th, palm forming a prominent 

 rounded angle with hind margin; alike in both sexes. Gnathopod 2, 2nd joint shallowly 

 channelled, distal angles not produced in lobes, 5th subtriangular, shorter in 3 than in 

 $, 6th in cJ oblong, widening slightly distally, its breadth subequal to length of 5th, 

 palm slightly oblique, shorter than hind margin, defined by a strong tooth which is not 

 bent inwards, with two strong teeth, the lower triangular, the upper more quadrate, 

 with a subsidiary denticle nearer the hinge, finger strong, closing on to palmar margin 

 but on the inside of the two teeth ; in ? less robust, palm more oblique and the palmar 

 teeth less strong. 



Peraeopods 3-5, 2nd joint elongate, narrow-oblong, front and hind margins sub- 

 parallel, but converging slightly distally, hind margin serrulate, postero-inferior angle 

 quadrate. Peraeopods 4 and 5 subequal in length. 



Remarks. Although in the form of the hand of gnathopod 2 this species approaches 

 longicornis, Wlkr., triodon, Schell., and trigonnrus, Schell., the length of the 5th joint at 

 once distinguishes it, apart from other characters. The 2nd joint of peraeopod 3 also 

 distinguishes it from longicornis. The similarity of the gnathopods in all the specimens 

 induces me to consider them the same species, in spite of the difference in size between 

 the 33 and the ?$. The large 33 of no. 2 look at first sight very like immature 33 of 

 dimorphus. 



Eurystheus distichon, Brnrd. (Fig. 141). 

 Barnard, 1930, p. 391, fig. 50 (3). 



Occurrence: 1. St. 42. South Georgia. 2 $$ 10-11 mm. 



2. St. 45. South Georgia. 20 33 9-12 mm., 27 ?$ 8-10 mm., 6 immat. 6-8 mm. 



3. St. 123. South Georgia. 5 33 8-10 mm., 4 $? 9-10 mm. 



4. St. 144. South Georgia. i(Jn mm. 



5. St. 159. South Georgia. 2 33 n-12 mm., 2 $$ 12 mm. 



6. St. 160. Shag Rocks. 1 $ 12 mm. 



Fig. 141. Eurystheus distichon, Brnrd. a. Telson. b. Gnathopod 2?. c. 2nd joint of peraeopod 5. 



Description of $. Resembling the 3 except that the notch on the palm of gnathopod 

 2 is shallower, and the 2nd joint of peraeopod 3 is less concave on the hind margin and 



29-2 



