. Bulletin of the British Museum (Natural History) Zoology. DEEP SEA PROTOBRANCHIA 60- 5o W/L- 80, 7o h/l- 5o- PL/ TU 145 12 3 4 Length mm Fig. 37 Ledella lusitanensis: An analysis of change in shape with growth as shown by the ratios posterior umbo length/length (PL/TL), height/ length (H/L) and width/length (W/L) plotted against length for specimens from Station Fig. 38 Ledella sandersi: Right lateral external view of the shell from Station 191. (Scale = 1 mm). the openings to the left digestive diverticula dorsally on the left wall. One is immediately posterior and ventral to the oeso
. Bulletin of the British Museum (Natural History) Zoology. DEEP SEA PROTOBRANCHIA 60- 5o W/L- 80, 7o h/l- 5o- PL/ TU 145 12 3 4 Length mm Fig. 37 Ledella lusitanensis: An analysis of change in shape with growth as shown by the ratios posterior umbo length/length (PL/TL), height/ length (H/L) and width/length (W/L) plotted against length for specimens from Station Fig. 38 Ledella sandersi: Right lateral external view of the shell from Station 191. (Scale = 1 mm). the openings to the left digestive diverticula dorsally on the left wall. One is immediately posterior and ventral to the oesophagus, the second is at approximately the same level and ventral to the tooth of the gastric shield. The shield is well developed. The style sac penetrates the upper half of between 1/3 - 1/2 of the ventral distance of the foot. The hind gut forms a single loop to each side of the body, the shape of the loops being similar to that of the right loop of Ledella modesta. The cross over point lies a short distance posterior to the ligament rather than immediately so as in L. pustulosa. Few specimens of this species were intact and only two could be sectioned. Both were male, in the smallest ( mm) Fig. 39 Ledella sandersi: Lateral view of specimen from the right side with the shell removed to show the arrangement of the body organs. (Scale = mm). For identification of parts see Fig. 35. the testis was slightly developed (2% of body area) while in the larger ( mm) 16% of body area was covered by testis. In the course of growth, the rostrum becomes more elongate with a slight shift in the total length/umbo-rostral length ratio (Figs. 36 & 37) and the dorsal margin becomes less convex. There is little change in the height/length and the width/length ratios. This species is somewhat similar in appearance to L. sublevis but the shell is slightly smoother, more elongate and. Please note that these images are extracted from scanned page images that may have been digitally en
Size: 2671px × 935px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollection, bookpublisherlondonbutterworths
