"There's another thing," continued Oxenden, "which is of immense importance, and that is their habit of cave-dwelling. I am inclined to think that they resorted to cave-dwelling at first from some hereditary instinct or other, and that their eyes and their whole morals have become affected by this mode of life. Now, as to ornamented caverns, we have many examples--caverns adorned with a splendor fully equal to anything among the Kosekin. There are in India the great Behar caves, the splendid Karli temple with its magnificent sculptures and imposing architecture, and the cavern-temples of Elephanta; there are the subterranean works in Egypt, the temple of Dendera in particular; in Petra we have the case of an entire city excavated from the rocky mountains; yet, after all, these do not bear upon the point in question, for they are isolated cases; and even Petra, though it contained a city, did not contain a nation. But there is a case, and one which is well known, that bears directly upon this question, and gives us the connecting link between the Kosekin and their Semitic brethren in the northern hemisphere." "What is that?" asked the doctor. "The Troglodytes," said Oxenden, with impressive solemnity. "Well, and what do you make out of the Troglodytes?" "I will explain," said Oxenden. "The name Troglodytes is given to various tribes of men, but those best known and celebrated under this name once inhabited the shores of the Red Sea, both on the Arabian and the Egyptian side. They belonged to the Arabian race, and were consequently a Semitic people. Mark that, for it is a point of the utmost importance. Now, these Troglodytes all lived in caverns, which were formed partly by art and partly by nature, although art must have had most to do with the construction of such vast subterranean works. They lived in great communities in caverns, and they had long tunnels passing from one community to another. Here also they kept their cattle. Some of these people have survived even to our own age; for Bruce, the Abyssinian traveller, saw them in Nubia. "The earliest writer who mentions the Troglodytes was Agatharcides, of Cnidos. According to him they were chiefly herdsmen. Their food was the flesh of cattle, and their drink a mixture of milk and blood. They dressed in the skins of cattle; they tattooed their bodies. They were very swift of foot, and were able to run down wild beasts in the hunt. They were also greatly given to robbery, and caravans passing to and fro had to guard against them.