. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. I46 THURLOW C. NELSON. to the outside at the heel of the foot. The cells of this gland are gorged with a transparent secretion which is not found in the much shrunken gland which characterizes the larva immediately after attachment. He believed that fixation was accomplished l>y the larva extending the foot until the heel came to a position near the upper anterior edge of the valve, and that the byssus gland then discharged its secretion, which, flowing between the left valve and the substratum, soon hardened and held the
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. I46 THURLOW C. NELSON. to the outside at the heel of the foot. The cells of this gland are gorged with a transparent secretion which is not found in the much shrunken gland which characterizes the larva immediately after attachment. He believed that fixation was accomplished l>y the larva extending the foot until the heel came to a position near the upper anterior edge of the valve, and that the byssus gland then discharged its secretion, which, flowing between the left valve and the substratum, soon hardened and held the larva fast. Stafford believed that the mantle played no part in the fixation process. My own observations show that Stafford was right in consid- ering the foot as the organ of final attachment. It is not thrust forward, however, as he held, but is brought to the median posi- tion. The extrusion of the mantle for a short period evidently aids in the quick and economical distribution of the cementing fluid as it is poured out of the byssus gland at the ventral edge of the left valve. This secretion hardens in less than 10 min- utes. In Fig. 3 are shown a number of newly attached larvae. I'll',. 3. Oyster larvae removed just after attachment and photographed from the left side to show the area covered by the cementing substance from the byssus gland. Magnified about 40 diameters. photographed from the left side to show the area covered by, and the distribution of, (he cementing material. The use of the foot in creeping over surfaces has been described in a number of larval bivalves, and it is the chief means by which the young molluscs obtain foothold in a favorable Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods
Size: 1740px × 1436px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
