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Specialized cilia of the byssus attachment plaque forming region in Mytilus californianus

✍ Scribed by A. Tamarin; P. Lewis; J. Askey


Publisher
John Wiley and Sons
Year
1974
Tongue
English
Weight
671 KB
Volume
142
Category
Article
ISSN
0362-2525

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✦ Synopsis


Abstract

The distal depression of the ventral pedal groove of Mytilus californianus was investigated by scanning and transmission electron microscopy. This part of the byssus forming system is responsible for the formation of the attachment plaque of the byssus thread.

The longitudinal pedal ducts open into this area and the floor of the distal depression is covered by specialized cilia which terminate as biconcave flattened discs or “paddles.” The disc is formed by a 360° curvature of the axoneme tip within the ciliary membrane. The diameter of the disc is about 1.33 μ while that of the shaft portion is 0.24 μ. There are about 11 cilia per square micron of surface area and the necks of the cilia are separated from each other by a web‐like extension of apical cytoplasm extending from the epithelial cells.

It is proposed that these specialized cilia function as microscopic spatulas for the application of the adhesive plaque material to substrate surfaces. The pattern of surface convection currents seen in vivo tends to support this hypothesis.