_Typhlomolge rathbuni._–It is of the greatest interest that a subterranean Perennibranchiate newt, in many respects closely resembling _Proteus_, has recently been discovered in Texas. There can be no doubt that similar conditions of life have produced these two forms from _Necturus_- and _Spelerpes_-like ancestors,[65] one in Europe, the other in North America, absolutely independently of each other. The limbs of _Typhlomolge_ are long and very slender, the four fingers and five toes are thin, free and pointed. The head is large, the mouth square. The eyes are completely hidden and the whole animal is colourless and white. The tail is furnished with a dorsal and a ventral fin. The very deep gular fold is nothing but the pair of united but large opercular flaps. The three pairs of gills are remarkable for their blade-like stalks, while the gill-lamellae proper are short and restricted to the tapering ends. Total length about 75 mm., of which the head measures 15, the tail 32 mm. This peculiar creature inhabits subterranean caves in Texas, to judge from the fact that all the specimens hitherto known have come up with the water of an artesian well 188 feet deep, near San Marcos. According to Blackford,[66] "the legs are used for locomotion and the animals creep along the bottom of the aquarium with a peculiar movement, swinging the legs in irregular circles at each step. They climb easily over the rocks piled in the aquarium, and hide in the crevices between them. All efforts to induce them to eat have been futile, as has also been the case with blind cave-fish in captivity, and they are {136}either capable of long fasts or live on infusoria in the water." It seems more reasonable to suppose that these newts live upon Crustacea, four kinds of which, all new to science, also came up with the water. FAM. 4. SIRENIDAE.–The three pairs of fringed external gills persist throughout life. The body is eel-like. Hind-limbs are altogether absent, while the fore-limbs are short and have three or four fingers. The maxillary bones are absent. With the exception of small teeth on the vomer the mouth is toothless, but the jaws are furnished with horny sheaths. The eyes are devoid of lids, but shine through the skin. [Illustration: FIG. 27.–_Siren lacertina._ × ½.]