Cephalic Glands in Sea Snakes (Pelamis, Hydrophis and Laticauda)

Abstract

Laticauda colubrina, Hydrophis ornatus and Pelamis platurus (Hydrophiidae) were investigated to determine the distribution and structure of their cephalic glands. Marine snakes do not possess glands not found in land snakes. All species of sea snakes examined possessed well developed Harderian, sublingual, anterior sublingual and venom glands. Labial glands were poorly developed laterally and there was a rostral expansion and enlargement of the supralabial in the premaxillary region. The nasal gland decreases in size as extrarenal salt secreting ability increases. P. platurus does not have a well developed nasal gland but its presence is confirmed in the serial sections of the head. Well developed nasal glands are present in H. ornatus and in L. colubrina. Mucoid cell types are found in the labial glands of L. colubrina and H. ornatus, but not in P. platurus. Secretion product when present and secretory granules in apical cytoplasm of cells in the labial glands are PAS-positive. The nasal and anterior sublingual glands are weakly PAS-positive in apical cell cytoplasm. The posterior sublingual is a single, elongate PAS-negative serous gland with scattered PAS-positive acini in its most anterior aspect. The paired anterior sublinguals are small serous glands with cuboidal secretory epithelium and no visible secretory product. The paired serous Harderian glands are PAS-positive with no mucoid cell types or visible secretory product. The venom glands are compartmentalized and contain cuboidal, columnar and mucoid cell types. Accessory venom glands were present in each species, circumscribing the main duct in the suborbital region.