Crocodiles come from the realm of Funan, being two or three zhang in length (i.e. 10 to 13 metres), with four feet, like a gecko in shape. They frequently swallow people whole, and the princes of Funan order people to catch these fish and place them in their moats, so that criminals can be thrown to them. If they are worthy of death, the crocodiles will eat them; if they are without guilt, this will be scented and they will not be eaten. Crocodiles are also called hulei; bears are able to control them, grasping their snouts and dragging them to the bank, then pulling them apart and eating them. Also known as gulei, they transform into tigers in autumn, having three talons, and issue forth from the two prefectures Si and Lei in Nanhai; Yingpan Village in Linhai has many of them.
Li Fang 李昉, et al., Taiping guangji 太平廣記 (Extensive Gleanings from the Era of Great Harmony), 10 vols (Beijing: Zhonghua shuju, 1961), x, 464.3822:
In the xinmao year of the Gandao era (1171 CE), no rain fell in Raozhou for a very long time, and the rivers’ flow was blocked. Three fishermen of Geshan Route went empty-handed to the Fan River to catch fish. Two went ahead, but one of them felt his two thighs suddenly turn cold as ice, feeling a slight trace of saliva, and, terrified lest there be the lair of a xiao beneath him, scrambled out urgently. One person alone did not see this and, having told his family he would provide for them, stayed to return at dusk. Two days later, his corpse floated some five li distant, with a fist-sized hole below the left thigh, the whole body entirely white, that being due to a xiao having curled around it and sucked his blood. In shape the xiao is just like an eel, eight or nine chi in length (c.2.7m), and is a kind of flood dragon. Among the Geshan populace, one Li Shi once caught one of these.
Hong Mai, Yi Jian Zhi, ii, 丙17.509
Hong Mai 洪邁, He Zhuo 何卓 (ed.), Yi Jian Zhi 夷堅志 (Record of Yi Jian) 4 vols (Beijing: Zhonghua shuju, 1981)
 The character xiao 𤡔 is treated by the MOE dictionary of character variants as a variation on xiao 梟 ‘owl’, but this story clearly indicates a rather interesting and different aquatic nature for the creature in question. See http://dict2.variants.moe.edu.tw/yitia/fra/fra01951.htm.