. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. LARVAL MUSCLES IN ABALONE ST. Figure 2. Parasagittal section through a larva of Haliotis kamlschatkana at 9 days after fertilization, showing the larval retractor muscle (LRM) projecting anteriorly from its shell attachment plaque (asterisk); distal portions of this muscle (arrowheads) extend into the velum (V) and along the ventral margin of the left pharyngeal pouch (PP). Other abbreviations: F = foot; MC = mantle cavity; MF = mantle fold; ST = statocyst; T = cephalic tentacle, VL = visceral lobe. Scale. 50 pm. Figu
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. LARVAL MUSCLES IN ABALONE ST. Figure 2. Parasagittal section through a larva of Haliotis kamlschatkana at 9 days after fertilization, showing the larval retractor muscle (LRM) projecting anteriorly from its shell attachment plaque (asterisk); distal portions of this muscle (arrowheads) extend into the velum (V) and along the ventral margin of the left pharyngeal pouch (PP). Other abbreviations: F = foot; MC = mantle cavity; MF = mantle fold; ST = statocyst; T = cephalic tentacle, VL = visceral lobe. Scale. 50 pm. Figure 3. Transmission electron micrograph of a portion of the lar- val retractor muscle attachment plaque, which consists of specialized perivisceral epithelial cells with intracellular filament bundles (ar- rowheads) and stubby microvilli (arrows) embedded in the fibrillar ma- trix of the protoconch (decalcified to allow sectioning). Scale. ^m. branes of both the muscle and adjacent epithelial cells have adherens-like junctional specializations that im- pinge on a thin layer of extracellular matrix lying be- tween these two cell types. Attachment plaques having this morphology have been described previously for both larval and adult gastropods (Bonar, 1978; Tompa and Watabe, 1976). Larvae also acquire musculature associated with the body wall and differentiating gut. The former consists of a complex network of intrinsic, subepidermal fibers that are particularly abundant within the foot of older larvae. The distal ends of shell muscles connect extensively with intrinsic musculature of the foot and velum. In this re- port. I do not describe either the gut or intrinsic body wall muscles in detail. Larval retractor muscle (LRM) and accessory larval reiractiir muscle (ACC) The images in Figure 4 are computer-generated recon- structions of transversely sectioned larvae at three stages of development: 52 hours, 5 days, and 9 days postfertil- ization. The reconstructions show trajec
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
