Dilly P N, Nixon M
Cell Tissue Res. 1976 Mar 16;167(2):229-41. doi: 10.1007/BF00224330.
A single layer of cell secrets the hard cephalopod beaks. The beccublasts are tall columnar cells that separate the beak from the surrounding buccal muscles, and must serve to attach these muscles to the beak. Within the cell layer there are three types of cells. The first, and most frequently found contain cell-long fibrils. These fibrils may have contractile and tensile properties. Complex trabeculae extend from the beccublasts into the matrix of the beak. The fibrils are attached to these trabeculae and at the other end of the cells they are anchored near to the beccublast-muscle cell interface, closely associated with the muscles that move the beak. The second group of cells contain masses of endoplasmic reticulum the cysternae of which are arranged along the long axis of the cell. These cells also contain dense granules and are probably the major source of beak hard tissue. It is probable that each cell secretes its own column of beak hard tissue. The third group of cells cells contains a mixture of fibrils and secretory tissue. In the beccublast layer there are changes in the proportion of the three types of cells depending upon the region sampled. In the region where growth is most active there are mostly secretory cells, whereas near the biting and wearing tip there are mainly anchoring type cells.
单层细胞分泌头足类动物坚硬的喙。成喙细胞是高柱状细胞，将喙与周围的颊肌分隔开，并且必定起到将这些肌肉附着到喙上的作用。在细胞层内有三种类型的细胞。第一种也是最常见的类型包含贯穿细胞的纤维。这些纤维可能具有收缩和拉伸特性。复杂的小梁从成喙细胞延伸到喙的基质中。纤维附着在这些小梁上，并且在细胞的另一端，它们锚定在成喙细胞与肌肉细胞的界面附近，与移动喙的肌肉紧密相连。第二类细胞含有大量内质网，其囊泡沿细胞的长轴排列。这些细胞还含有致密颗粒，可能是喙硬组织的主要来源。很可能每个细胞分泌其自身的一列喙硬组织。第三类细胞含有纤维和分泌组织的混合物。在成喙细胞层中，根据取样区域的不同，这三种类型细胞的比例会发生变化。在生长最活跃的区域，主要是分泌细胞，而在咬合和磨损的尖端附近，主要是锚定型细胞。
