Caudal mucous pit Caudal mucous pit The caudal mucous pit, or caudal mucous horn, is an anatomical structure on the tail end of the foot of various land snails and slugs, terrestrial pulmonate gastropod mollusks. The function of this pit is the resorption of mucus when the gastropod is moving (see also Muratov 1999). An incorrect and yet often-used term for this structure is the "caudal gland". This area also used to be referred to by the term "caudal pore". Families of snails and slug where a caudal mucous pit exists in every species included: Families/subfamilies where is caudal mucous pit exists only
Fish scale from other structures that arise from the integument. Development starts near the caudal fin, along the lateral line of the fish. The development process begins with an accumulation of fibroblasts between the epidermis and dermis. Collagen fibrils begin to organize themselves in the dermal layer, which leads to the initiation of mineralization. The circumference of the scales grows first, followed by thickness when overlapping layers mineralize together. Ctenoid scales can be further subdivided into three types: Both cycloid and ctenoid scales are overlapping, making them more flexible than cosmoid and ganoid scales. Unlike ganoid scales, they grow in size through