66 THE VOYAGE OF H.M.S. CHALLENGER. 



Station 146, December 29, 1873; lat. 46' 46' S., long. 45° 31' E. ; 1375 fathoms; 

 bottom, Globigerina ooze. 



Station 147, December 30, 1873; lat. 46° 16' S., long. 48° 27' E. ; 1600 fathoms; 

 bottom, Diatom ooze. 



The above cited Monograph of Grube contains a description and figures of a species of 

 Serolis (Serolis tuberculata) which diifers from all the species known at that time and 

 from ;dl those already described in the present Eeport by the characters of the fifth and 

 sixth thoracic segments ; the tergum of the fifth segment, which is generally narrower 

 than the preceding ones, is in this species extremely narrow, not measuring more than one- 

 sixth of the diameter of the segment in front, while the tergum of the sixth thoracic 

 segment has entirely disappeared : the Challenger obtained two specimens of this same 

 species, Serolis tuberculata, besides examples of four other species which agree Avith 

 Serolis tuberculata in the characters just mentioned ; nil these species are inhabitants of 

 the shallow waters off the southern and eastern coasts of Australia, and form a well- 

 marked group, agreeing with each other in a number of structural points. These species 

 I have briefly described in my " Preliminary Eeport," and named as follows : — Serolis 

 pallida, Serolis aiistraliensis, Serolis elongata, Serolis minuta, and Seivlis longicaudata ; 

 all these species, with the exception of Serolis minuta, agree witli each other and with 

 Serolis tubercidata in the following points, some of which are peculiar to the group, 

 while others again are not confined to the group, but are also to be found in other species. 



They are all of small size ; the females are larger than the males (?). The thoracic 

 epimera are short and closely applied together for then- whole length, while the epimera 

 of the two abdominal segments are very short and not 2>rolonged beyond the anterior 

 margin of the caudal shield. The tergum of the fifth thoracic segment is extremely 

 narrow ; the tergum of the sixth segment is obsolete in the middle line, the suture which 

 separates it from the succeeding first segment of the abdomen passes forwards and 

 disappears underneath the segment in front {cf. PI. VI. fig. 1) in Serolis tuberculata and 

 Serolis 'pallida ; in Serolis australiensis, Serolis elongata, and Serolis longicaudctta the 

 general appearance of the two last thoracic terga is the same, but a careful inspection 

 shows that the posterior sutures of both segments become obsolete just before the middle 

 line of the body, so that which apparently is the tergum of the first abdominal segment 

 in reality includes also the middle part of the terga of the two last thoracic segments. 

 In Serolis minuta the fifth and sixth thoracic segments are not quite so narrow as in the 

 other Australian species. The fifth segment is divided o3' by a sutural line which is 

 entirely continuous from one side of the body to the other ; the sixth segment, however, 

 though proportionately somewhat broader, resembles that of Serolis australiensis, &c., in 

 being fused mesially with the succeeding abdominal segment. In the other Australian 

 species the rostrum is long, reaching beyond the first joint of the anterior pair of 



