114 



J.A. ALLEN AND H.L. SANDERS 



Fig. 18. Ledella acinula. Four shells in outline, from Knorr station 299 from the Guyana Basin, in right lateral view to illustrate changes in shape with 

 increasing size. Scale = 1mm. 



feeding aperture ventral to the siphonal embayment. The adductor 

 muscles are relatively large, the anterior ovate and the posterior 

 more circular in cross section. The anterior sense organ lies far 

 anterior, ventral to the anterior adductor. The palps and gills are 

 moderate in size with relatively few ridges (up to 15) and plates (up 

 to 17) respectively. The foot has a well-defined neck, this is probably 

 related to the relatively large height of the shell. There is a large 

 'byssal' gland present in the heel of the foot. The hind gut first makes 

 a single loop on the right side of the body before passing to the left 

 side of the body between the oesophagus and the inner face of the 

 anterior adductor muscle. On the left side of the body the hind gut 

 forms a double coil. Because of the anterior penetration of the gut to 

 the left side, the mouth is displaced some distance posterior to the 

 anterior adductor muscle. 



Ledella aberrata (new species) 



Type specimen. Holotype BMNH 1995045; paratypes BMNH 

 1995046. 



Type LOCALITY. Chain cruise 60, station 247, Argentine Basin, 

 43°33.0'S 48"58.1'W, 5208-5223m 



80- 



70 J 



60- 



■ o-o - 



o 

 ■°o" 



PL/, 



50- 





2 3 



Length (mm) 



I 

 4 



Fig. 19. Ledella acinula. The ratios of height to total length (H/L)(open 

 circles) and post-umbonal length to total length (PL/L)(closed circles) 

 plotted against total length to show changes in shell proportions with 

 increasing length. Specimens from Knorr station 299 from the Guyana 

 Basin. 



Material: 















Cruise 



Sta Depth 



(m) 



No 



Lat 



Long 



Date 



Gear 



ARGENTINE BASIN 













Atlantis II 



242 4382- 



2 



38°16.9'S 



51'56.1'W 



13.3.71 



ES 



60 



4402 















247 5208- 



34 



43°33.0'S 



48'58.1'W 



17.3.71 



ES 





5223 















252 4435 



4 



38°29.8'S 



52"09.1'W 



22.3.71 



ES 



GUYANA BASIN 













I.Charcot 



KG13 5100 



1 



10°47.6'N 



42°40.4'W 



20.11.77 



KG 



Biovema 















NORTH AMERICA BASIN 











Chain 50 



85 3834 



1 



37°59.2'N 



69"26.2'W 



5.7.65 



ES 



WEST EUROPEAN BASIN 











Chain 106 



330 4632 



3 



50'43.4'N 



17'51.7'W 



24.8.72 



ES 



I.Charcot 



DS23 4734 



5 



46"32.8'N 



10°21.0'W 



1.11.72 



DS 



Polygas 















Biogas II 



DS32 2138 



1 



47°32.2'N 



08°05.3'W 



17.4.73 



DS 



Biogas IV 



DS54 4659 



7 



4631.1'N 



10°29.2'W 



21.2.74 



DS 



Cryos 



DS68 4550 



2 



46'26.7'N 



1073.9'W 



19.6.74 



DS 



Biogas V 















J.Charcot 



DS78 4706 



18 



46°31.2'N 



10'23.8'W 



25.10.74 



DS 



Biogas VI 



DS79 4715 



17 



46"30.4'N 



10'27.1'W 



26.10.74 



DS 





DS80 4720 



3 



46°29.5'N 



10°29.5'W 



27.10.74 



DS 





DS81 4715 



2 



46°28.3'N 



10"24.6'W 



27.10.74 



DS 



INCAL 



CP10 4823 



1 



48"25.5'N 



15'10.7'W 



31.7.76 



CP 





DS11 4823 



2 



48"18.8'N 



15'11.5'W 



1.8.76 



DS 





WS034829 



18 



48°19.2'N 



15°23.3'W 



1.8.76 



WS 





CP1 1 4823 



1 



48°20.4'N 



15"14.6'W 



1.8.76 



CP 





OS02 4829 



1 



48"19.2'N 



15°15.9'W 



2.8.76 



OS 





WS104354 



1 



47"27.3'N 



09°39.9'W 



11.8.76 



WS 



CAPE BASIN 













J.Charcot 



DS05 4560 



2 



33°20.5'S 



02°34.9'E 



30.12.78 



DS 



Walvis 















