90 U.S. NATIONAL MUSEUM BULLETIN 29 5 



Right valves horn Albatross 2763: USNM 121373, length 1.48 mm, 

 height 0.80 mm; USNM 121374, length 1.49 mm, height 0.79 mm. 



Left valves from Albatross 2763: USNM 121375, length 1.51 mm, 

 height 0.86 mm; USNM 121376, length 1.62 mm, height 0.90 mm. 



Affinities. — Specimens of the Tulear population are larger and 

 rather higher than those from St. Thomas Island; the right valve is 

 also slightly more broadly rounded posteriorly and hence less sym- 

 metrical in lateral view. Specimens from Albatross 2763 are very 

 much larger than either the St. Thomas or Tulear populations but 

 are essentially identical in shape. 



Bythocypris elongata Brady, 1880 



Figure 46a, b 



Bythocypris elongata Brady, 1880, p. 47, pi. 6: fig. la-c. — ?Chapinan, 1910, p. 



428. — ?Key in van Andel and Postma, 1954, p. 219, pi. 3: fig. 11. 

 Not Bythocypris elongata LeRoy, 1943, p. 358. 



Diagnosis. — Carapace twice as long as high, rather compressed and 

 thin. Ventral margin nearly straight, posterodorsal margin straight 

 and sloping steeply, dorsomedian margin nearly straight, anterodorsal 

 margin straight and sloping gently, intersections of marginal sections 

 obscurely angulate. 



Material. — Lectotype specimen in Challenger slide 124, British 

 Museum (Nat. Hist.) cat. no. 157, a single right valve from Challenger 

 station 325, north of Tristan d'Acunha, at 1425 fms depth. 



Specimens, 22 at Anton Bruun stations 361B, G, H, 363E, K, 

 367G, 368C, 369A, 409A, 413 from the Mozambique Channel, all 

 apparently juveniles. 



Distribution. — Described by Brady (1880) from 1425 fms depth 

 north of Tristan d'Acunha. Reported by Chapman (1910) at 1050 

 fms near Fiji; by Key (1954) in the Gulf of Paria at much shallower 

 depths (4 to 152 m). Recorded in the present study from 11 stations 

 in the south-central portion of the Mozambique Channel, at depths 

 ranging from 400 to 3750 meters and usually below 1190 m. 



Dimensions.— Juvenile (?) specimen USNM 121379, left valve, 

 length 1.71 mm, height 0.81 mm; right valve, length 1.70 mm, height 

 0.71 mm. 



Affinities. — The specimen figured by Key (1954) is somewhat less 

 elongate and more highly arched dorsally. The Anton Bruun specimens 

 are identical in shape to the Challenger lectotype. 



Bythocypris affinis (Brady), 1886 

 Bythocypris affinis affinis (Brady), 1886 



Figure 45a-d 



Bairdia affinis Brady, 1886, p. 195, pi. 14: figs. 6-7. — Brady and Norman, 1889, 

 p. 242. 



