REPORT ON THE ISOPODA. 7 



The head is broader than long, with very large laterally placed eyes ; there is a long 

 spatulate rostrum which projects beyond the end of the second joint of the antennules ; 

 on either side of this the anterior margin of the head is depressed for the articulation 

 of the antennules, the antero-lateral margins being again salient, though not projecting 

 so far as the rostrum. The head as well as the rest of the body is very convex. 



The width of the body gradually increases up to the third segment of the thorax, thence 

 onwards it does not greatly diminish, so that the body has a cylindrical elongate form. 



The first two segments of the thorax are about equal in length ; the three succeed- 

 ing segments progressively diminish in length ; the two last segments are again 

 rather longer. The first four have their antero-lateral margin prolonged into a 

 truncated process and the postero-lateral margin also ; the margins of all the segments 

 as well as of the abdominal shield are fringed with scattered hairs. The epimera of all 

 the thoracic segments, with the exception of the first, are visible on a dorsal view ; in 

 the second, third, and fourth segments the epimera are bilobed (see fig. 2), in the 

 remaining segments they are unilobate. 



The abdominal shield is subpentagonal and terminates in a short blunt process. 



The antennules (fig. 4) have a long flagellum composed of a considerable number of 

 joints ; the peduncle consists of four joints ; the first is stout and rounded, the second 

 shorter and more slender, the third of about the same length as the second but more 

 slender, the fourth very small. 



The antennae are broken off at the third joint in both specimens ; the third joint is 

 short, but longer than the two preceding ; it is furnished with an articulated scale on 

 the outer side (see fig. 5). 



The mandible has a three jointed palp. 



The thoracic appendages (fig. 3) are all similar to each other; the two first joints are 

 stout and rather short, the third is shorter, and the fourth is as stout and of about the 

 same length as the first two ; the terminal joint of the limb is very short and biun- 

 guiculate. 



The under surface of the abdomen (in the female) is entirely covered by the convex 

 operculum. 



The uropoda are defective, or may possibly be wanting, as there was no trace of them 

 in either specimen. 



This species agrees with Jsera in the general form of the body, and in the non- 

 prehensile character of the first thoracic appendages. 



On the other hand, it agrees with Janira in the multiarticulate flagellum of the 

 antennules, and in the presence of a rudimentary exopodite to the antenna?. 



It would be no escape from the difficulty to assign this species to the genus Ianthe, 

 since the latter appears to be hardly distinguished from Jsera, except by the great 

 length of the uropoda, which are like those of Janira ; and these appendages are, as has 



