SECTION II 

 OSTRACODA 



FROM UPTHRUST MUDS ABOVE THE DRYGALSKI GLACIER, SOUTH- 

 EAST OF MOUNT LARSEN 



GENERAL REMARKS ON THE COLLECTION 



From amongst the washed debris which yielded the Foraminifera of the accompanying 

 report, there were found a few ostracodal valves. They were all single, showing that 

 the connecting ligament of the hinge-line in every case had been fractured and 

 severed, and that deposition of sediment had not taken place before the carapace was 

 disunited by the action of local currents. This is often seen in recent soundings, 

 where, although at considerable depths, aided by the influence of currents, the valves are 

 frequently found separated. 



Five species are herein described, one of which is new, whilst some others help to 

 elucidate already known but imperfectly understood species. They are comprised 

 in the genera Pontocypris, Cythere, Cytheropteron, and Cytherideis. All the previously 

 described species are Southern Oceanic forms, although one has also been recorded 

 from Torres Strait. One of the species, it is worth noting, shows close alliance with 

 fossil and recent Arctic and sub-Arctic species. 



The evidence of these ostracoda as to their bathymetrical distribution is much 

 the same as that of the foraminifera ; for they seem to indicate deposits, generally 

 speaking, of at least 100 fathoms, if not of greater depth. 



DESCRIPTION OF THE OSTRACODA 

 Family— CYPRIDjE 



Genus — Pontocypris, G. 0. Sars, 1865 

 Pontocypris subreniformis, G. S. Brady (PI. IV, Fig. 1) 



Pontocypris (1) subreniformis, G. S. Brady, 1880, Rep. Chall., Zool., vol. i, Pt. Ill, 

 p. 38, PI. XV, Figs. 6a-6d ("Pontocypris (?) subtriangularis, sp. n.") on plate. 



There is a slight confusion in the Challenger Report over what appear to be two 

 distinct forms. On p. 38 a Pontocypris is described under the name of P '. (?) subreni- 

 formis, sip. n. The description there given corresponds with our Antarctic specimens. 

 Reference to Plate XV, Figs. 6a-6d, of the same Report, and given with the description, 

 will show that the species by mistake is there named Pontocypris (?) subtriangularis, 

 sp. n. Further, another figure, evidently of a distinct species, but named Pontocypris (?) 

 subreniformis, is to be found on Plate VII, Figs. 5a-5d. The latter figures, which, by 

 the way, appear to be placed posterior extremity upwards, are closely related to a 

 fossil Bythocypris from the Wimmera borings in Victoria ; and as Dr. G. S. Brady 



37 



