DEEP-SEA PROTOBRANCHIA (BIVALVIA) 



67 



60 



Fig. 104 Yoldiella jeffreysi. A comparison of selected specimens 

 from a number of deep-sea Basins showing the range in shell 

 shape. The shell outlines of each specimen are drawn in dorsal 

 and right lateral view, a & b, Sta. 197, Angola Basin; c, Sta. 288, 

 Guyana Basin; d, Sta. 334, North America Basin; e & f, Sta. 259, 

 Argentine Basin; g, Sta. 316, West European Basin; h, Sta. 85, 

 North America Basin. (Scale =1.0 mm). 



obvious (Fig. 109) and by October the gonads had largely 

 filled the body. 



Yoldiella enata (new species) 



Type locality. R.V. Knorr, Sta. 301, Guyana Basin, 

 29.1.1972, 8°12.4'N, 55°50.2'W, Epibenthic Dredge, 

 2487-2500 m. 



Type specimen. Holotype: BM(NH) 1992033. Paratypes: in 

 collection held by J. A. Allen. 



Material. 



Cruise Sta Depth No Lat Long Gear Date 



(m) 



GUYANA BASIN 



Knorr 25 301 2487- 175 8°12.4'N 55°50.2'W ES 29. 1.72 



2500 

 303 2842- 23 8°28.8'N 56°04.5'W ES 1. 3.72 



2853 



40 



W\L 



• ••«• % 



80 



60 

 60 

 50 



H\L 



. ..'or-.:;*;^. 



PL\TL 



• . W'^^ 



60 



40 

 80 



60 

 60 

 50^ 



W\L 



. •* •. •' 



H\L 



*•..«••• *' 



PL\TL 



• • • • 



12 3 4 



Length (mm) 



Fig. 105 Yoldiella jeffreysi. Variation in ratios of height H/L, width 

 W/L and postero-umbonal length PL/TL to length against length 

 of a, samples from Sta. 126, North America Basin (large closed 

 circles) and Sta. 259, Argentine Basin (points); and of b, samples 

 from Sta. INCAL DS 07, West European Basin (points) and Sta. 

 6704, Canary Basin (large closed circles). 



ES 18. 8.66 



Several specimens of this species are included in a mixture of 

 species contained with U.S. Natl. Mus. No. 108197, labelled 

 Yoldiella pygmaea Munst. None of these correspond to Leda 



NORTH AMERICA BASIN 





Atlantis II 118 1135- 20 32°99.4'N 



64°34.9'W 



1153 - 32°19.0'N 



64°34.8'W 



