. Bulletin of the British Museum (Natural History) Zoology. Fig. 73 Ledella ultima: Growth series of shells from Station 126 in lateral outline to show change in shape with increasing size. (Scale = 1 mm).. Locality. Challenger St. 122, off Brazil, 9°05.'S, 34°51'W, 640 m. Both specimens of L. semen labelled 'type' have disinte- grated so that it is impossible to make comparisons with the type material of L. parva and with the present specimens. From the descriptions of L. semen and L. parva and from what little can be made out of the fragments of the type species of L. semen, it is possible t
. Bulletin of the British Museum (Natural History) Zoology. Fig. 73 Ledella ultima: Growth series of shells from Station 126 in lateral outline to show change in shape with increasing size. (Scale = 1 mm).. Locality. Challenger St. 122, off Brazil, 9°05.'S, 34°51'W, 640 m. Both specimens of L. semen labelled 'type' have disinte- grated so that it is impossible to make comparisons with the type material of L. parva and with the present specimens. From the descriptions of L. semen and L. parva and from what little can be made out of the fragments of the type species of L. semen, it is possible that L. parva and L. semen are synonymous. This conclusion was also reached by James (1978). James (1978) noted that Smith (1885) in his original description confused anterior for posterior teeth and vice versa. This we confirm. Verrill & Bush (1897) described L. parva as a separate species from L. semen on the basis of the teeth. Thus, while it may well be that the two species are synonymous, it would be unwise to be categorical. Note too that L. parva also resembles L. oxira (p. 148) and may be a sibling species. Description (Figs. 76 & 77). Shell small, ovate, inequilateral, smooth, growth lines very fine; umbos posterior, slightly raised, slightly inclined posteriorly; anterior margin obtusely rounded, posterior margin with short rostrum, antero-dorsal margin curves from umbo in smooth curve with anterior margin, postero-dorsal margin proximally straight, more dis- tally gradually slopes to a point opposite the posterior edge of hinge plate then more steeply to tip of rostrum, posterior ventral margin sinuous, ventral margin rounded, moderately convex, shallow depression in shell from umbo to postero- ventral margin; hinge plate moderately strong, broad, posterior hinge plate short, strongly curved with 9 chevron- shaped teeth, anterior plate less curved with 12 teeth; liga- ment amphidetic, internal, triangular in shape. The dimensions of the two intact specimens
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