. Bonner zoologische Monographien. Zoology. 32. Fig. 15: Diagrammatic dorsal view of coelomic cavities of a 1 gill slit larv a of Bvauchiostoma lanceolatum. a - anus. HN - Hatschek's nephridium. mo - mouth opening. MC - myocoel. PP - preoral pit. RC - rostral coelom. \'C - Ventral coelom. Igs - first priman.^ gill slit. (Number of segmental myotomes arbitrary.) The rostral coelom arises from the right diverticulum of Hatschek that pinches off from the intestine at about the neurula stage with eleven segments (Plates 3 & 6). The epithelium of this pouch is prismatic in the earlier stages, b
. Bonner zoologische Monographien. Zoology. 32. Fig. 15: Diagrammatic dorsal view of coelomic cavities of a 1 gill slit larv a of Bvauchiostoma lanceolatum. a - anus. HN - Hatschek's nephridium. mo - mouth opening. MC - myocoel. PP - preoral pit. RC - rostral coelom. \'C - Ventral coelom. Igs - first priman.^ gill slit. (Number of segmental myotomes arbitrary.) The rostral coelom arises from the right diverticulum of Hatschek that pinches off from the intestine at about the neurula stage with eleven segments (Plates 3 & 6). The epithelium of this pouch is prismatic in the earlier stages, but develops into a thin layer of typical coelothelic cells in the larval stage (Plates 10-16A). In the lar- vae the rostral coelom is ver}^ spacious reaching from the anterior tip of the ani- mal, where it is situated just beneath the notochord. posterior to the region behind the first primary gill slit, thus spanning over a length of approximately 300 \xm nearly a third of the animafs entire length. The rostral coelom divides into two narrow canals, where the gill slit opens, passing the gill slit dorsally and with a narrower canal ventrally (Plates 13 & 14). The rostral coelom is in continuity with the ventral coelom. Just in front of the anterior rim of the mouth opening the dor- sal cells of the rostral coelom are differentiated as muscle cells (Fig. 12A: Plate IIB). Such a differentiation of the dorsal cells into muscle cells occurs again behind the first primary gill slit at the posterior end of the rostral coelom (Plates 13B & 16). Throughout its course the rostral coelom comes in close contact \\ ith the endostyle, the club-shaped gland, and the preoral pit. The ventral coelomic canal of the larva extends from the region of the first pri- mary gill slit where it consists of very narrow lacunae, which are in contact wilXi the rostral coelom. to the region several ,um anterior to the anus (Plates 13-17).. Please note that these images are extracted from scanned pa
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Keywords: ., bookcentury1900, bookcollectionbiodiversity, booksubjectzoology
