The demons were always given some shape, animal or human, for it was a necessary corollary of the stage of religious thought to which the belief in demons belongs, that the demon must not only be somewhere, though invisible to mankind, but also _in_ something that manifests life. Among animals, those calculated to inspire terror by their mysterious movements were chosen, as serpents appearing and disappearing with startling suddenness, or ugly scorpions, against whom it was difficult to protect oneself, or the fabulous monsters with which graves and pestiferous spots were peopled. Regions difficult of access--the desert, the deep waters, the high mountains--were the favorite haunts of the demons. Some of these demons were frequently pictured in the boundary stones between fields, in order to emphasize the curses hurled upon the head of him who should trespass on the lawful rights of the owner of the land.[348] It is to such demons embodied in living form that epithets such as the 'seizer,' the 'one that lurks,' and the like apply with peculiar aptness. In a tablet belonging to a long series of incantations,[349] we find references to various animals--the serpent, the scorpion, monsters--that are regarded as the embodiment of demons. In the distinctively religious art, the evil spirits are often pictured as ugly monsters that were to inspire terror by their very aspect. Depicted on the monuments, singly or in groups,[350] the shape of wild animals was given to the head, while the remainder of the body was suggestive of a human form. With gaping mouths and armed with some weapon, they stand ready to make an attack. The Assyrian kings, up to the latest period, acknowledged the power of the demons by making huge representations of them, which they placed at the approaches, entrances, and divisions of their temples and palaces, in the hope of thus securing their protection. The great bulls and lions with human heads--so familiar to every one--are but another form of the same idea. These colossal statues were actually known by the name _shedu_, which we have seen is one of the general terms for 'demon.' But as a general thing, this personal phase of the demon's existence is lost sight of. Even though embodied in animal form, the demons could make themselves invisible to man; and since most of their actions were performed in secret, so that people were totally at their mercy, the differentiation of the demons became a factor of minor importance. With so large a quantity of demons at command, it was difficult to hit upon the one who was manifesting himself by some evil at any given moment. Accordingly, instead of a single mention, a number or a group were enumerated, and the magic formulas pronounced against them in concert. We have one such group of seven to whom quite a number of references are found in the incantation texts. A section in one of these texts gives a vivid description of them:[351]