74 



J.A. ALLEN, H.L. SANDERS AND F. HANNAH 





DS05 2503 



1 



56°28.1'N 



iril.7'W 



DS 



18. 



7.76 











- 56°27.6'N 



11°12.0'W 











DS09 2897 



7 



55°07.0'N 



12°52.6'W 



DS 



20. 



7.76 











- 55°08.1'N 



12°53.2'W 











DS14 4254- 



1 



47°32.6'N 



9°35.7'W 



DS 



8. 



8.76 







4548 





- 47°32.9'N 



9°35.5'W 











DS16 4268 



2 



47°29.8'N 



9°33.4'W 



DS 



9. 



8.76 











- 47°30.3'N 



9°33.4'W 









GUINEA BASIN 



















DS20 2514 



2 



2°32.0'S 



8°18.1'W 



DS 







SIERRA LEONE BASIN 















Atlantis II 



149 



3861 



1 



10°30.0'N 



18°18.0'W 



ES 



7. 



2.67 



31 



















ANGOLA BASIN 

















Atlantis II 



195 



3707 



7 



14°49.0'N 



9°56.0'W 



ES 



19. 



5.68 



42 









- 14°40.0'N 



9°54.0'W 











196 



4612- 

 4630 



2 



10°29.0'N 

 - 10°29.5'W 



9°03.0'W 

 9°04.0'W 



ES 



21. 



5.68 





197 



3865- 

 4595 



5 



10°29.0'N 

 - 10°29.0'N 



9°04.0'W 

 9°04.0'N 



ES 



21. 



5.68 





198 



4559- 

 4566 



10 



10°24.0'N 

 - 9°47.0'N 



9°09.0'W 

 10°29.0'W 



ES 



21. 



5.68 





199 



3764- 

 3779 



2 



9°49.0'N 

 - 9°41.0'N 



10°33.0'W 

 10°55.0'W 



ES 



22. 



5.68 



GUYANA BASIN 

















Knorr 25 



291 



3859- 

 3868 



1 



10°06.1'N 



55°14.0'W 



ES 



26. 



2.72 





303 



2842- 

 2853 



2 



8°28.8'N 



56°04.0'W 



ES 



1. 



3.72 



Y. fabula is wide-spread at abyssal depths throughout the 

 Atlantic in small but persistent numbers in most of the 

 Atlantic Basins. Low population density and low sampling 

 density probably explains the lack of records in the Guyana & 

 Canaries Basins. Depth range: 2503-5223 m. 



Shell description (Figs. 119-121). Shell small, moderately 

 swollen, 'bean'-shaped, inequilateral, post umbonal length 



Fig. 118 Yoldiella sp. Lateral views of two shells taken from Sta. 

 119, Angola Basin. (Scale = 1.0 mm). 



40-46% of total length, sculpture regular with conspicuous 

 ridges, periostracum straw coloured, often discoloured and 

 brown at valve margins; umbo relatively large, posterior in 

 position and inflated, directed posteriorly; proximal dorsal 

 margins slightly convex either side of umbo, proximally 

 evenly curved to rounded anterior and posterior margins, 

 ventral margin long, smooth curve; hinge plate moderately 



Fig. 119 Yoldiella fabula. 

 Lateral views of two shells 

 from the right and left sides 

 respectively and a left valve 

 to show details of the 

 hinge-plate, a, Jeffreys 

 collection USNM No. 199590 

 labelled Leda sericea Jeffr. 

 St. 21, 1476 fm. N.W. 

 Ireland, Pore. Ex. 1870; b, 

 USNM No. 199589 labelled 

 Leda sericea Jeff . St. 19a, 

 1366 fm, W. of Ireland, Pore. 

 Ex. 1869; c, USNM No. 

 697343 labelled Yoldiella 

 expansa Jeffreys 49°37'N, 

 13°34'W. S.W. of Ireland. 

 (Scale = 1.0 mm). 



