The body wall of cheilostome bryozoa. I. The ectocyst of Watersipora nigra (Canu and Bassler)
✍ Scribed by William C. Banta
- Book ID
- 102902676
- Publisher
- John Wiley and Sons
- Year
- 1968
- Tongue
- English
- Weight
- 964 KB
- Volume
- 125
- Category
- Article
- ISSN
- 0362-2525
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✦ Synopsis
The cuticle of Watersipora nigra is at first translucent, but it later becomes black and differentiates into two layers. It is composed, at least in part, of a protein-polysaccharide complex. Calcified parts are three-layered: ( 1 ) an outer, cuticlular layer, ( 2 ) a calcium carbonate skeleton deposited on a matrix of acid mucopolysaccharide, and ( 3 ) a "skeletal membrane." The relationships of these layers indicate that the skeleton is intracuticular. A layer of cuticular material, the "intercalary cuticle" is present in lateral walls, but not trznsverse walls; it may become calcified in some species. The cuticles of calcified and uncalcified parts of cheilostomes are not necessarily homologous.
This paper is the first in a series dealing with the body wall of cheilostome Bryozoa, with special emphasis on the frontal wall. The first three papers will especially concern the anatomy of Watersipora nigra (Canu and Bassler). This species was chosen for the following reasons: ( 1 ) it is locally abundant; (2) its distribution is world-wide, permitting duplication of observations by other workers; ( 3 ) it is not complicated by polymorphism or secondary calcification; and ( 4 ) it possesses a welldeveloped hypostegal cavity.
METHODS AND MATERIALS
The materials used in this study were collected at the Southwestern Yacht Club Marina, on San Diego Bay, San Diego, California, during February, March and April, 1967. Speciments were kept on ice four to five hours, then fixed in Bouin's fluid, Gilson's fluid, 10% formalin in sea water, or 1% osmium tetroxide buffered at pH 7.2 with sodium carbonate.
Osmium-fixed material was decalcified, dehydrated, and embedded in epon according to the method of Pease ('64). Sections were cut at 0.5 u on glass knives with a Porter-Bloom MT-1 ultramicrotome, affixed to slides by heat, and stained in toluidine blue 0, Richardson's stain, or safranin and gentian violet. Sections were mounted in immersion oil, since most resins (balsam, Permount, etc.) cause fading.
Material fixed in Bouin's, Gilson's or formalin was sectioned by standard paraf-