. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CHAETOPTERUS LARVAL ONTOGENY 325. Figure 5. Larvae, stages L4 and L5. Anterior and posterior mesotrochs are marked by arrowheads, (a. h) Stage L4 larvae at 30 days in dorsal and ventral views, (c-e) Stage L5 larvae at 60 days in dorsal, lateral, and ventral views respectively. The locations of adult setiger rudiments are labeled in (d). Note the appearance of the red adult ocelli, visible in (e) along with the persistent larval ocelli, ao, adult ocellus; hg. hindgut; lo, larval ocellus; mg, midgut; nr. notopodial rudiment of
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CHAETOPTERUS LARVAL ONTOGENY 325. Figure 5. Larvae, stages L4 and L5. Anterior and posterior mesotrochs are marked by arrowheads, (a. h) Stage L4 larvae at 30 days in dorsal and ventral views, (c-e) Stage L5 larvae at 60 days in dorsal, lateral, and ventral views respectively. The locations of adult setiger rudiments are labeled in (d). Note the appearance of the red adult ocelli, visible in (e) along with the persistent larval ocelli, ao, adult ocellus; hg. hindgut; lo, larval ocellus; mg, midgut; nr. notopodial rudiment of setigers A1-A9; pa, palp rudiment; pal, palette rudiment of setigers B3-B5; pol, post-oral lobe; pp. papilla; prl, pre-oral lobe; st, stomodeum. Scale bars are 100 ftm. the expression pattern of ft-titbulin visualized by in situ hybridization (Fig. 4b, c). The fact that in situ hybridization to p-tubiilin transcripts failed to detect a distinct VNC prior to this stage suggests that the VNC had not yet formed. Segmental boundaries are not distinguishable, by conven- tional microscopy, anterior to the mesotrochs in any tissue. However, in situ hybridization to jB-tubii/iii transcripts re- veals that reiterated ganglionic cell populations, presumably segmental, are present at this stage (Fig. 4b, c). Bilateral ganglionic cell populations are also visible in the overtly segmented anlagen of setigers B2-B5 (Fig. 4b). Capacious coelomic cavities with distinct septa surround the larval foregut, as seen in frontal section (Fig. 3c). Transverse sections at the middle of the larva reveal bilat- eral coelomic cavities, separated by a ventral mesentery, medial to the nerve cord. Between these cavities and the gut, the ventral blood vessel is located at the midline (Fig. 3f). A particularly distinctive cell type is that of the ciliated cells of the trochal bands. These are large prismatic cells with a uniform granular cytoplasm (Fig. 3g). They are extended along the anterior-posterior axis
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
