Ductless glands are glands that secrete hormones directly into the bloodstream rather than through ducts. The hormones then travel through the bloodstream to reach their target cells. The adrenal gland, pancreatic gland, and parathyroid gland are all examples of ductless glands. The salivary gland, on the other hand, is an example of an exocrine gland, which secretes substances through a duct to an epithelial surface, such as the skin or mucosa. Therefore, the correct answer is salivary gland.