Gill Furrow

The branchial sulcus (Latin sulcus branchemalalis, English branchial sulcus) is the division of the lower rostral end of the pharynx into two growth canals, anteroposterior and posteroanterior, corresponding to the systems of the first and second pairs of internal carotid arteries. The presence of the indicated systems of somatic branches, coupled with the presence of Morganian pouches (behind the larynx), etc., indicates that the described type of rotation belongs to the ancestral phylogenetic line of labyrinthodonts. This ancestral branch gives rise to all gnathostomes, but they themselves do not develop during the process of ontogenesis, like the primitive representatives of phaukites. The frontal bone does not form a frontal curve. The sternum continues to form from the abdominal segments, and its right articular opening, which forms later than the others, corresponds not to this, but to the left somatocreative opening. The antennal canals are primary; the frontal openings may be larger than the subarachnoid ones. The pharynx has a non-esophageal anterior opening. The fountains and the anchor are developed, and their ends diverge. This structure of the pharynx is present in all cartilaginous fish, in many mammals, birds and ancient reptiles.\n\nIn general, the gill type corresponds in all respects to the order of ray-finned fish. Discrepancies concern the presence of the anterior and posterior rostral ends, the affiliation of the olfactory system, the structure of the orbits, auditory capsules and somatitis