. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. growth pattern, with all larvae from the same brood being at the same developmental stage. Distribution of cilia on the velum The ciliature of a larva of shell length 400 jam is shown in Figure 4A. A concavity about 70-80 /urn in diameter is visible in the most central and apical sector of the velum (Fig. 4B). Located in its base is a group of small cilia, the apical cilia (AC), which are randomly distributed and are not organized into the apical tuft characteristic of planktonic veligers, but lie in the same position. Surro
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. growth pattern, with all larvae from the same brood being at the same developmental stage. Distribution of cilia on the velum The ciliature of a larva of shell length 400 jam is shown in Figure 4A. A concavity about 70-80 /urn in diameter is visible in the most central and apical sector of the velum (Fig. 4B). Located in its base is a group of small cilia, the apical cilia (AC), which are randomly distributed and are not organized into the apical tuft characteristic of planktonic veligers, but lie in the same position. Surrounding this depression is a bare region about 60 /urn wide, delimited by a single belt of cilia constituting the inner preoral ciliary (IPO ring. Figure 2. In a larva of Ostri'u chilcnsix with a shell length of about 300 fitn. the cilia first appear on top of the velum, as well as in the food groox e and mouth region, (a, b) Superior-lateral view of the cilia that will form the OPC band; scale bars 60 JLUII and S JLUII respectively; arrows indicate future OPC. (c) Short cilia covering the adoral food groove (FC) and the mouth region (ventral aspect); scale bar 80 /jm. The IPC form a ring of single cilia (Fig. 4C), each one about 15-20 ;um long. Outside the IPC ring is a naked area, 9-10 ju,m wide, which is surrounded by a large ring of OPC. Oilier preoral cilia The OPC form a band, about 10-15 wide, of two rows of cirri, or composite cilia (Waller, 1981), which are oriented radially from the center of the velum (Fig. 4D, E). This is the dominant ring in the velum because of its width and the size and complexity of its cirri. Each cirrus is roughly 80 ju,m long and is composed of 50-100 cilia. ©(H)®©. Figure 3. Schematic representation of the velum in a laic pedneligcr ol Ihircn <ihilciisi.\ ( "400 /xm shell length) in lateral view. Ciliar, bands are identified in an enlarged section of the velum. AC: apical cilia; AOC: adoral cilia; IPC: inner preoral cilia; OP
Size: 2107px × 1186px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
