. Bulletin of the Natural History Museum Zoology. . Fig. 9 Bargmannia amoena sp. nov. A. Upper, B. lower, and C. lateral views of young nectophore from specimen collected during JSL II Dive 1449. Scale bar = 2 mm. the nectosac is variable, according to the developmental stage. It ranges from a narrow, median U-shaped indentation to a marked emargination across most of the width of the nectosac. As noted above the shape of the mouth-plate varies according to the size of the specimen. On either side of the ostium there is a tract of small ectodermal cells extending up toward the end of the outer
. Bulletin of the Natural History Museum Zoology. . Fig. 9 Bargmannia amoena sp. nov. A. Upper, B. lower, and C. lateral views of young nectophore from specimen collected during JSL II Dive 1449. Scale bar = 2 mm. the nectosac is variable, according to the developmental stage. It ranges from a narrow, median U-shaped indentation to a marked emargination across most of the width of the nectosac. As noted above the shape of the mouth-plate varies according to the size of the specimen. On either side of the ostium there is a tract of small ectodermal cells extending up toward the end of the outer branch of the apico-lateral ridges. These tracts are longer than those seen on the young nectophores of B. elongata and, again, are difficult to discern on the adult nectophores. Bract (Figure 10). There are three pairs of bracts per cormidium. Each is thin and leaf-like, with a slight thickening in the central region of the proximal half. The dorsal surface is slightly convex, and the ventral one slightly concave. In general their size is in proportion with that of the nectophores, with those of the largest specimens measuring up to 18 mm in length. No patches of ectoder- mal cells were observed. However, in each cormidium, each successive pair of bracts tends to be slightly larger than the pair proximal to it. The proximal part of each bract is slightly asymmetri- cal to allow for insertion onto the stem. The bracteal canal extends to about two-thirds to four-fifths the length of the bract. It remains in close contact with the ventral wall of the bract at all times. There is much variation in the shape and form of the bracts, but two basic types can be distinguished; both having two pairs of lateral teeth. In one type, which make up the first two pairs of bracts in each cormidium, the bracts are relatively symmetrical. The more distal pair of lateral teeth are very variable in shape, ranging from being virtually absent to being quite marked (Figure 10A, B, D). In the second
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Keywords: ., bh, bookcentury1900, bookcollectionbiodiversity, bookleafnumber62
