. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 324 S. Q. IRVINE ET AL cells. Also visible are light-emitting photocytes ventrolat- eral to the intestine; these, described by Henry (1989). are functional by stage L2. Staining with alcian blue (not shown) reveals large mucosal cells dorsal and lateral to the stomodeum. Late period, ll-30da\s. This period is morphologically similar to the preceding, the most obvious difference being the addition of a pair of dorsomedial eyes. The stomach becomes still larger relative to the overall body, and the mesotroch widens with it. Th
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 324 S. Q. IRVINE ET AL cells. Also visible are light-emitting photocytes ventrolat- eral to the intestine; these, described by Henry (1989). are functional by stage L2. Staining with alcian blue (not shown) reveals large mucosal cells dorsal and lateral to the stomodeum. Late period, ll-30da\s. This period is morphologically similar to the preceding, the most obvious difference being the addition of a pair of dorsomedial eyes. The stomach becomes still larger relative to the overall body, and the mesotroch widens with it. The pygidial papilla becomes longer and more distinct. The apical tuft is still present along with the lateral bristles, both of which are lost by the end of this stage. These observations correlate well with previous descriptions (Enders. 1909; Cazaux, 1965). //; situ hybridization with a (3-titbulin riboprobe reveals cells with extensive ciliation in the apical tuft, stomodeum, and mesotroch (Fig. 4a). However, at this stage our probe does not reveal neural elements. Stage L4—30-60 days (Fig. 5a, b): Size: approx. mean 600 X 400 /MIII Cilian- structures: apical tuft lost; two mesotrochs Ocelli: 6; 2 pairs lateral, 1 pair medial References: Cazaux (1965) pit. 4, rigs. 7-8; Enders (1909) pit. II, rig. 10 Two major changes from stage L3 are evident in this stage. The first is the appearance of a second trochal band just anterior to the existing mesotroch. The second change is the advent of overt segmentation in the region between the posterior mesotroch and the pygidium. Three distinct annu- lar bulges are visible in this region; as becomes evident in later stages, these are rudiments of setigers B3-B5. The segmental anlage of the anterior 11 setigers are not apparent by visual inspection, but the prospective cell populations of the parapodia are present. This was shown by staining with an anti-Distal-less antibody that recognizes the prospective apical cells of body wall outgro
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
