1884.] DURING THE VOYAGE OF H. M.S. ' CHALLENGER. ' 331 



The first five are all inhabitants of deep water ; the remaining 

 species were dredged in shallow water off the coasts of Southern 

 and Eastern Australia. 



1. Serous bromleyana (Suhm). 



This species has already been briefly characterized by the late Dr. 

 v. Willemoes Suhm from two specimens obtained near the Antarctic 

 ice-barrier. These two specimens are the largest contained in the 

 'Challenger' collection; the male measures 54 millim. in length and 

 56 millim. in greatest breadth ; the length from the anterior end of 

 the rostrum to the termination of the 6th epimeron is 78 millim. 

 The female is somewhat smaller tban the male, and measures 45 

 millim. in length, 39 millim. in breadth, and 62 millim. from the 

 rostrum to the end of the 6th epimeron. This species is one of the 

 largest of the Isopoda. Like many of the other deep-sea species it 

 has extremely long spine-like epimera, which are longer and project 

 further outwards from the body in the males than in the females. 



The cephalic shield stands out in relief from the surface of the 

 first thoracic segment, from which it is separated by a suture lying 

 in a deep depression ; its anterior margin is prolonged into a short 

 rostrum ; the lateral portions of the cephalic shield extend for some 

 way anterior to the rostrum, and are cut off from the rest by a ridge 

 which passes almost in a straight line from the rostrum to the sides 

 of the cephalic shield ; the surface is raised into three rounded 

 prominences, two on the inner side of the eyes and a median T- 

 shaped prominence between them. The eyes are inconspicuous, 

 owing to their pale greyish colour and absence of corneal facets. 

 The epimera of the first thoracic segment are divided into three 

 portions by a Y-shaped ridge ; the other epimera gradually increase 

 in length up to the sixth, which is the longest ; both the epimera of 

 the abdominal segments are extremely long and reach beyond the 

 limit of the caudal shield in the male ; in the female the last epimera 

 barely reach the end of the caudal shield. 



The caudal shield is oval in form and longitudinally carmate, the 

 posterior end is slightly excavated ; at about the middle of the caudal 

 shield near the lateral margin is a notch on either side ; the terminal 

 appendages of the body are attached about halfway down the 

 caudal shield. The colour (in spirit) is a dark slate-blue. 



Station 156, 1975 fathoms; Station 1G4a, 410 fathoms; Station 

 168, 1100 fathoms; Station 169, 700 fathoms. 



2. Serolis ne^era, n. sp. 



This species almost rivals Serolis bromleyana in size ; the largest 

 male specimen measures 43 millim. in length and 47 millim. in 

 greatest breadth, the length of the sixth (longest) epimeron being 

 38 millim. ; the female is smaller than the male, the largest specimen 

 measuring 40 millim. in length, 40 millim. in greatest breadth, the 

 sixth epimeron measures 31 millim. 



The males of Serolis necera differ from the females therefore by 

 their greater size, and also by the greater leugth of the epimera, 



