扬子鳄皮肤腺结构与发育的初步观察

扬子鳄有三种皮肤腺:背腺、泄殖腔麝腺和下颌腺。背腺位于背中线左右两侧第二行鳞片下方,其确切位置个体间差异很大,如表1。幼鳄背腺形态多种多样,但显示出是一种退化器官,未观察到腺开口,也未观察到半成鳄和成鳄的背腺,因此扬子鳄背腺可能不具功能。泄殖腔麝腺位于泄殖腔腹唇内,梨形,腺管开口于泄殖腔腹壁,成体腺腔很大,腺的底部壁较厚,腺细胞明显地分成若干小叶,其它部位壁较薄,小叶不明显,属全泌腺,分泌油脂物,繁殖期特别发达,但性未成熟个体亦具功能,是一种信息素下颌腺位于下颌后方两侧皮肤内,圆柱状,脉管开口于下颌腹侧皮肤表面,成体腺腔不规则,腺壁厚,从包囊到腺腔,腺细胞可明显地分成三个区,属全泌腺,分泌油脂物,在繁殖期特别发达,此腺到性成熟才具功能。

STRUCTURE AND DEVELOPMENT OF THE INTEGUMENTAL GLANDS OF THE CHINESE ALLIGATOR

There are three sets of integumental glands in Chinese alligator, the dorsal glands, the cloacal musk glands and the mandibular glands.The dorsal glands lie beneath the second tow of scales on the two sides from the mid-dorsal line. Their accurate situation is variable among individual as table 1. Their morphology is variable, but they show that they are a degenerated organ. No opening of the gland is observed and probably it has no function. The cloacal glands lie within the lips of the cloacal slit. It is pear-shaped and opens to the intraventral surface of the cloaca. In the adult, the gland is found to contain a large lumen. The wall in the bottom of the gland is thicker. In this region the glandular cells are divided into some lobules by the connective tissue, and in other region the wall is thiner and the lobules aren't obvious. The cloacal glands are holocrine gland. The secretion is an oily substance with a rich odor, during the breeding season when the glands are the most active, so that the secretion is used by the sexes. But the glands are also functional in the young alligator and are used as a pheromone. The mandibular glands are situated in the skin on the throat, on the lateral sides of the lower jaw. It is cylindrical in shape and opens to the ventral surface of the lower jaw. The gland lumen is irregular in the adult. The wall of the gland is thicker, from the capsule to the lumen three regions of the glandular cells may be made out. The mandibular glands are holocrine gland. They secrete the oily substance with a rich odor especially in the breeding season. This glands are functional when the animal is sex-maturity.