. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. GEL FILLED PRIMARY BODY CAVITIES 29. Figure 4. (A, B) Arms of the ophiopluteus of Ophiopholis aculeata with most of the epidermis stripped away: ink particles are suspended in isosmotic MgSO4. A blob of gelatinous material is almost detached in B. Scale lines are 50 Mm. (C) Arm of the echinopluteus ofStrongylocentrotusfranciscanus with most of the epidermis stripped away; ink particles are in seawater. C is at lower magnification than A and B. All speci- mens are strongly compressed by the coverglass. in brownian motion imme
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. GEL FILLED PRIMARY BODY CAVITIES 29. Figure 4. (A, B) Arms of the ophiopluteus of Ophiopholis aculeata with most of the epidermis stripped away: ink particles are suspended in isosmotic MgSO4. A blob of gelatinous material is almost detached in B. Scale lines are 50 Mm. (C) Arm of the echinopluteus ofStrongylocentrotusfranciscanus with most of the epidermis stripped away; ink particles are in seawater. C is at lower magnification than A and B. All speci- mens are strongly compressed by the coverglass. in brownian motion immediately adjacent to the invisi- ble surface of the bounding gel. I therefore concluded that the irregular pockets were the torn surface of a gel that filled the body cavity. Gelatinous material also extended into arms of plutei from which the epidermis had been stripped (O. aculeata in isosmotic MgSO4. in seawater; Fig. 4). In one dissection of 5. franciscanus an isolated blob of gel remained skewered on an arm rod like a kebab. Thus even body parts with skeletal support also had gelatinous support. The posterior part of the bodies of the ophioplu- teus and echinopluteus also contained gelatinous mate- rial (same two species). The gel partially or completely surrounded the gut (Fig. 3E) and esophagus of fragments of the bipinnaria of A. minima (dissected in isosmotic MgSO4). There was also evidence against the alternative hy- pothesis that hydrostatic pressure maintains the larval shape. When tornariae () and auriculariae (P. cal- ifornicus and large larva with wheel ossicles) were torn in half in seawater, the thin epidermis did not collapse like a punctured balloon. The same result was obtained with the bipinnaria of A. miniata in both isosmotic MgCl2 and seawater. Fragments of all three larval forms maintained the form that they had in the intact larva (as in Fig. 2 for auricularia and bipinnaria). Also, anterior and posterior halves of auriculariae (P.
Size: 2946px × 848px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
