Both chitin and cuticles are insoluble substances essential for providing structural support to organs and skeletal systems, particularly in loose tissue. In cephalopods, they are primarily responsible for forming beaks and covering the entire stomach in adult animals. The beaks of cephalopods are critical organs for cutting food into small pieces during feeding. The upper beaks have a distinct characteristic: their inner surface is hard and contains growth lines, which can be used to estimate the age of the animals and determine seasonality, with broader and harder lines forming during the summer. The beaks, composed of chitinous structures, are affected by heat during the summer, as are all chitinous structures. Both the upper and lower beaks have a sugar structure mixed with chitin during the animals' growth, giving them a shiny appearance under an electron microscope. Age determination by growth lines is an accurate method, especially in cultured animals, as the growth lines precisely indicate age and seasonality throughout the life cycle. The stomach of Octopus vulgaris has a thick and robust wall, and in adult animals, a cuticle layer (first recorded in this study) was observed through anatomical examination. This cuticle inside the stomach is clear and elastic, serving to protect the stomach during the consumption of hard prey. The second stomach contains goblet cells that secrete carbohydrates and mix saliva with stomach secretions to aid in digestion. These goblet cells have a unique, elongated shape and are fewer in number compared to those in the esophagus of the same specimens. Finally, the beaks are the primary organs for cutting food during feeding. The buccal mass, which houses the beaks, can be easily removed by hand during dissection due to the presence of large invaginations created by pressure when the octopus captures hard prey.