REVISION OF RECENT BAIRDIIDAE 57 



The more complex muscle-scar divisions, lack of differentiated 

 opaque pattern, and huge size suggest that this species or species 

 complex should be removed to a new genus. Until better preserved 

 material can be studied, this form is temporarily assigned to 

 Paranesidea. 



Paranesidea? species 1 



Figure 27a, b 



Material. — From Anton Bruun stations 380A, C, 160 subfossil 

 specimens. 



Distribution. — Walterson Shoal, depths 935 and 950 m. 



Dimensions. — Specimen USNM 121315, left valve, length 1.31 mm, 

 height 0.86 mm. 



Specimen USNM 121316, right valve, length 1.29 mm, height 0.78 

 mm. 



Remarks. — This form is characterized by considerable ventral 

 inflation, nearly symmetrical lateral outlines with caudate posterior, 

 broadly arched dorsal margin in left valve, denticulate margins, and 

 smooth exterior with tiny normal pore canal pits. The two top rows 

 of the adductor muscle-scar pattern are divided into 3 scars rather 

 than two and separated somewhat; the resulting configuration has a 

 rather macrocypridid aspect. For this and other reasons summarized 

 above, this form should be assigned with P. ? albatrossa, new species, 

 to a new genus rather than Paranesidea. 



Paranesidea species 2 



Figure 29 



Material. — Two adult males and one female recently dead at 

 Anton Bruun station 421 A. 



Distribution. — Near Mombasa, Kenya; depth 34 m. 



Dimensions.^ — Adult male specimen USNM 121318, left valve, 

 length 0.90 mm, height 0.61 mm; right valve, length 0.90 mm, height 

 0.55 mm. 



Adult female specimen USNM 121319, left valve, length 0.85 mm, 

 height 0.55 mm; right valve, length 0.85 mm, height 0.54 mm. 



Remarks. — Conspicuous characters of this form include the com- 

 plicated opaque pattern, marginal denticles of right valve, and 

 striate frills of left valve. Its shape and size are very like P. spon- 

 gicola, new species, from which it differs by its smooth exterior, 

 different opaque pattern, and less caudate posterior. 



Paranesidea species 3 



Figure 28 c-i; Plate 1: figures 1, 2 



Material. — One adult male living at Ghardaqua, Egypt, in 

 washings of algae at low tide level (sample HA-33). 



