ИСТИНА

Pholoe belongs to the Sigalionidae family. They are all predators and use an axial muscular pharynx with two pairs of jaws, but fine morphology of their feeding apparatus is poorly studied. Our research focused to the problem of morphological and functional structure of the feeding apparatus of Pholoe assimilis using light and scanning electron microscopy, microcomputed tomography and histological sections. Our result demonstrated that the pharynx is a flattened dorso-ventrally muscular cylinder about 1 mm long. At the distal end of the inverted pharynx there are 18 large terminal papillae and jaws. The jaw apparatus consists of two pairs of jaws, while each pair forms a single functional structure. Each jaw consists of three parts: a tooth, a wing and a body. The function of the tooth is to capture prey, the jaw canal passes through it for excretion of glands secret. Presumably the gland canal begins at the intersection of the wing and the body from the inside and comes to the surface near the tip of the tooth. The functional role of the wing and body is unknown; they are probably supporting structures for the tooth. An elemental analysis of the jaws showed that Pholoe jaws are not mineralized, they consist of scleroproteins and contain iodine. The obtained data on the histological structure showed that the pharynx is connected to the pharyngeal bag by bundles of radial fibers, covered with cuticle, its wall is formed by thick layers of radial and longitudinal muscles. There is a circular muscle at the base of the pharyngeal papillae, it is a sphincter that responsible for jaw’s closing. There are two types of glands in the pharynx. The first one associated with the terminal papillae and is responsible for the secretion of mucus in them; the second one associated with jaws, and presumably secretes a venom. Jaw’s glands are located on the medial surface of the wing of the jaw. Each jaw is associated with one gland.