88 ^-S- NATIONAL MUSEUM BULLETIX 2 95 



Remarks. — Many fossi] and a few Recent species have been 

 misassigned to Bythocypris because of insufficient attention to muscle- 

 scar pattern. For example, Bythocypris actites Benson, 1959 (USXM 

 113120, 113121) is a Krithe, as are the specimens identified by Tres- 

 sler (1941) as Bythocypris ohtusata Sars (USXM 153749, 153748) 

 and Bythocypris bosguetiana (Brady) (USX'M 153746, 153747). 



Bythocypris reniformis Brady, 1880 



Figure 45j-m 





Bythocypris reniformis Brady, 1880, p. 46, pi. .5: fig. la-1. — ?Chapman, 1941,, 

 p. 195. 



Diagnosis. — Carapace relatively robust, moderately inflated, alll| 

 outhnes gently curved; left valve ^vith straight ventral margin,, 

 broadly and nearly equally rounded anterior and posterior margins,, 

 broadly arched dorsal margin highest at midpoint, nearly symmetri-' 

 cal in lateral view; right valve not as high, ventral margin gently 

 indented, dorsal margin only slightly arched, anterior margin broadly 

 rounded, posterior region obUquely rounded with steeply sloping' 

 posterodorsal margin; radial pore canals and false pore canals abun- 

 dant and quite long; muscle scars and normal pore canals conspicuous 

 as opaque areas on otherwise transparent carapace. 



Material. — Lectotype and two syntype specimens in Challenger 

 slide no. 123, British Museum (Nat. Hist.) cat. no. 80.38, from station 

 24, north of St. Thomas I., at 390 fms. 



Seven subfossil valves in additional sediment from Challenger 24. 



Subfossil specimens, 108 from Anton Bruun stations 363L, 410A, 

 413B, and especially 365D; 75 subfossil specimens from Albatross 

 station 2763. 



Distribution. — Identified by Brady (1880) from Challenger sta- 

 tions off St. Thomas (Culebra; Island at 390 fms. off X'orth Brazil at 

 675 and 350 fms, off Prince Edward Island at 50-150 fms; by Chap- 

 man (?) from southeast Australia at 505 and 470 fms. 



Abundant near Tulear, Madagascar, and elsewhere on the western 

 Madagascar coast to depths of 3100 m. Extremeh abundant in 

 Albatross station 2763, south of Rio de Janeiro, at 1227 m. 



Dimensions. — Ijeft valves hom. Anton Bruun 365D: USXM 121366, 

 length 1.11 mm, height 0.62 mm; USXM 121367, length 1.14 mm, 

 height 0.66 mm; USXM 121368, length 1.20 mm, height 0.71 mm; 

 USX'^M 121369, length 1.11 mm, height 0.62 mm. 



Right valves from Anton Bruun 365D: USXM 121370, length 

 0.98 nun, height 0.53 mm; USXM 121371, length 1.07 mm. height 

 0.61 mm; USXM 121372, length 1.09 mm, height 0.59 mm; USXM 

 121377, length 1.20 mm, height 0.64 mm. 



