580 " THETIS " SCIENTIFIC RESULTS. 



I have restored it to the present genus on account of the striking^ 

 resemblance which it bears to the next species, that being in ray 

 opinion an undoubted Iphimedia. 



Haswell gives the colour as red with brown dots, and the 

 length at first as 3/30 in., but subsequently as 3/20 in., thus 

 varying between 2'5 and 3'75 mm. The latter statement was no 

 doubt a correction of the earlier one. In 1882 he adds Port 

 Jackson (dredged) as the place of capture. This form was not 

 included in the " Thetis " collection. 



IPHIMEDIA DISCRETA, sp. nov. 

 (Plate xlix.) 

 Station 57. 



This species is in many respects so closely in agreement with 

 Iphhnedia obesa, Rathke, that it will be convenient to confine 

 the description almost entirely to those points in which it differs 

 from Rathke's species. 



The specimen examined was an adult female, containing about 

 eight large eggs, its first antenniB imperfect, the second broken, 

 and the last three joints missing from all the peraeopods. Also 

 each of the third uropods had lost one of the rami. 



The tumid peraeon has the first and last segments very long 

 in comparison with the shortness of the intervening five, so far 

 agreeing with /. avtbigua rather than J. obesa. In common with 

 both, this species has the rostrate head, the seventh peraeon seg- 

 ment and the first three segments of the much compressed pleon 

 each with a pair of postero-dorsal teeth. Of the side-plates the 

 first has the lower angle quadrate instead of acute, but the rest 

 are in agreement with /. obesa, the last three not having a tooth- 

 like postero-lateral angle as in /. ambiqua. In like manner the 

 produced tooth at the lower angle of the third pleon segment 

 agrees with the former species in being surmounted by a larger 

 tooth near to it, not remote as in the latter. 



The eyes have very numerous small components. The first 

 joint of the first antennae is apically produced into one long and 

 two small teeth. In the second antennae the basal joints are 

 short, the penultimate joint of the peduncle doubtful, the ultimate 

 slender, carrying a flagellum of twenty-five joints, this part 

 detached, but entangled with the other appendages. . 



The mouth-organs diff"er from those of /. obesa as figured by 

 Professor Sars in the following points. On one mandible the 

 accessory plate is a long narrow piece, minutely denticulate at its 

 apex, on the other it is either wanting or in coalescence with the 

 principal cutting edge to which it in the latter case contri- 



