110 U.S. NATIONAL MUSEUM BULLETIN 2 95 



Diagnosis. — Carapace thin and very compressed; dorsal margin of 

 left valve gently arched, dorsal interlamellar space open, anterior and 

 posterior margins narrowly and nearly equally rounded, ventral 

 margin horizontal; lateral outHne of right valve approaching rectiUnear, 

 median dorsal margin short and straight, anterodorsal portion short 

 and sloping, posterodorsal margin longer and more steeply sloping. 



Female genital lobe of pecuUar structure, consisting of broad 

 hemicircular base and long, doubly coiled tube encased in curved 

 tubular sheath. Male ^vith large symmetrical brush-shaped organ, 

 slightly refiexed first thoracic leg. 



Dimensions.— Adult female USNM 121625, left valve, length 1.46 

 mm, height 0.89 mm. 



Juvenile male (?) USNM 121626, left valve, length 1.52 mm, height 

 0.92 mm. 



Affinities. — The genital lobe structure is unlike any other de- 

 scribed; the other appendage morphology is similar to that of Z. 

 heterodoxa (Chapman) . No copulatory organ is observable on the only 

 male (juvenile?) specimen. 



Zabythocypris species 1 



Figure 57d 



Material. — Four subfossil specimens from Albatross stations 5650 

 and 2808 in the Gulf of Mexico and Indonesia. 



Dimensions. — Specimen USNM 121398, left valve, length 1.42 

 mm, height 0.89 mm. 



Affinities. — These specimens, which may include two sexes or 

 even two species, are similar to but not identifiable with Z. exaltata 

 (Brady) and Z. ancipita, new species. 



Anchistrocheles Brady and Norman, 1889 



Anchistrocheles Brady and Norman, 1889, p. 110. — Brady, 1890, p. 496. — Miiller, 

 1908, p. 100. 



Type-species. — Anchistrocheles Jumata Brady, 1890, p. 497, pi. 3: 

 figs. 13, 14 (by Brady and Norman, 1889). 



Diagnosis. — Carapace small, very delicate, extremely compressed 

 especially marginally, reniform outline; broad fused marginal zone and 

 abundant straight radial pore canals; bythocyprid adductor muscle- 

 scar pattern. 



Antenna with short thick podomeres and stout distal claw; distal 

 claws of antenna and thoracic legs with sharply angled tiny terminal 

 hooks; vibratory plate of first thoracic leg with 4 closely spaced, 

 featherless setae and few or no other setae; thoracic legs with podo- 

 meres 3 and 4 completely fused, podomere 1 mthout ventral setae; 

 mandible and maxiUa elongated and with reduced setae. 



