. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 126 L. R. BICKELL AND S. C. KEMPF CG CE EY. PLG ST FIGURE 9. Sagittal section through a larva of M. leonina in which the mantle fold (MF) has retracted from the aperture of the shell. Note the eye (EY), statocyst (S), cerebral ganglion (CG), pedal ganglion (PG), and pleural ganglion (PLG) of the larval nervous system and the thin cephalic epithelium (CE), the elongate but low profile of the foot (F), and the gonadal rudiment (G). The section also passes through the stomach (ST), right digestive diverticulum (RD), and the int
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 126 L. R. BICKELL AND S. C. KEMPF CG CE EY. PLG ST FIGURE 9. Sagittal section through a larva of M. leonina in which the mantle fold (MF) has retracted from the aperture of the shell. Note the eye (EY), statocyst (S), cerebral ganglion (CG), pedal ganglion (PG), and pleural ganglion (PLG) of the larval nervous system and the thin cephalic epithelium (CE), the elongate but low profile of the foot (F), and the gonadal rudiment (G). The section also passes through the stomach (ST), right digestive diverticulum (RD), and the intestine (I). FIGURE 10. Mid-sagittal section through a larva of M. leonina just prior to the onset of meta- morphosis showing the hypertrophied cephalic epithelium (CE), a ceratal rudiment (C), the propodial swelling (P) on the ventral surface of the foot, the gonadal rudiment (G), and the many large lipid deposits (arrowheads) within the walls of the stomach (ST) and left digestive diverticulum (LD). A vestigial radular rudiment (asterisk) has evaginated from the ventral wall of the esophagus (E) at the level of the cerebral commissure (CC). The nervous system of M. leonina becomes extensively elaborated during larval development. By the time of mantle retraction, the pedal and pleural ganglia are clearly recognizable, the cerebral ganglia have enlarged, and a pair of eyespots have differentiated (Fig. 9). The pedal ganglia differentiate adjacent to the statocysts and are connected to each other by a pedal commissure and to their respective ipsilateral cerebral ganglion by a cerebropedal connective. Each pleural ganglion extends from the ipsilateral cerebral ganglion via a broad cerebropleural connective. Between the stages of mantle retraction and the onset of metamorphosis, the buccal and rhino- phoral ganglia differentiate. Three additional developments that occur during the larval phase of M. leonina are the development of the pulsatile larval heart soon after mantle retrac
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
