placoid

shagreen Untanned sharkskin retaining the placoid scales;

鲨鱼皮保留盾的未鞣制鲨鱼皮；

denticle The tooth-like scale of elasmobranchs; placoid scale of cartilaginous fish; also called dermal denticle.

细板鳃类的像牙齿一样片;软骨鱼的盾;称为表皮的细。

dentine A hard mesodermal material in teeth and some scales (cosmoid, ganoid and placoid scales) produced by odontobasts.

齿质组成牙齿或某些片(硬与盾)中层的坚硬物质。

enamel A shiny hard material covering the dentine of teeth and the surface of some scales (cosmoid and placoid scales).

珐琅有光泽的坚硬物质包覆在牙齿及一些片(圆与盾)表面。这是脊椎动物所产生最坚硬的物质。

stomodeal denticles Special placoid scales lining the mouth and pharyngeal cavities of some Elasmobranchii, e.g. Heterodontus.

口道小齿在一些板鳃亚纲的嘴巴与咽洞里的特化盾，例如虎鲨。