132 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



IDOTEA JAPONICA, new species. 



Body slender, elongated, five times longer than broad, witti sides 

 parallel. A dorsal median keel extends the entire length of the body. 



Color, brownish 

 yellow. 



Head with the 

 anterior margin 

 deeply and roundly 

 excavate and with 

 the anterolateral 

 angles broadly 

 rounded. Eyes 

 situated on the ex- 

 treme lateral mar- 

 gin in the median 

 transverse line. 

 The first pair of 

 antennse reach only 

 a little beyond the 

 second joint of the 

 peduncleof the sec- 

 ond pair of anteunse. The second pair of antennae are half as long as 

 the body, and when retracted would extend to the middle of the fifth 



Fig. 1.— Idotea japonica. X 2. 



2. — Idotea ocho- 



TENSIS. X 2. 



thoracic segment ; first 

 duncle short and con 

 tero-lateral angles in a 

 ond and third joints 

 len gth ; fourth an d fifth 

 length, and each equal 

 third taken together; 

 posed of 14 joints, and 

 shorter than the pe- 

 duncle. 



Segments of the tho- 

 rax about equal in 

 length. First segment 

 with a deep excavation 

 and with an tero lateral 

 angles rounded. Epi- 

 mera narrow ; those of 

 the second, third, and 



joint of the pe- 

 cealed by the au- 

 dorsal view; see- 

 nearly equal in 

 joints equal in 

 to the second and 

 flagellum corn- 



fourth segments 

 cupying only the 



oc- 



an- 

 terior half of the lat- 

 eral margins; those of 

 the fifth and sixth segments, the anterior two-thirds, and of the seventh 

 segment, the entire margin. 



Fig. 3.— a, antenna of second pair 

 OP Idotea japonica ; 6, antenna 

 op second pair of Idotea ocho- 



TENSIS. X 8. 



Fig. 4.— OS, opercular 

 VALVE of Idotea ocho 



TENSIS ; 6, OPERCULAR 



VALVE OP Idotea jap" 



ONICA. X 8. 



