Among the permanent residents in dark places we have, among mammals, the moles, which habitually live in burrows of their own make. In Mammoth Cave lives a rat--Neotoma pennsylvanica. In Marengo Cave, Indiana, white-footed mice have established themselves. Although with unimpaired eyes, they have acquired ears and whiskers longer than the rest of their kind living outside. In Florida occurs a blind lizard--Rhineura floridana. It burrows in the ground, and is colorless and blind. [Illustration: FIG. 1.--The cave salamander of the Mississippi Valley (_Spelerpes maculicauda_).] Of salamanders, one blind species lives in European caves. In the large caves of the eastern United States no blind salamanders have been found, although other species, especially Spelerpes maculicauda, abound. In the caves of Missouri a veiled-eyed salamander, Typhlotriton, has been described within recent years by Stejneger. Still another salamander, Typhlomolge, having rudimentary eyes, has been cast up from an artesian well at San Marcos, Texas, and occurs in the cave streams about that place. The most abundant of the blind vertebrates, both in individuals and in species, are the blind fishes. These, from their geographical distribution, may be separated into three groups: (1) Those inhabiting the depths of the ocean; (2) those inhabiting dark places along the shores of the ocean; (3) those inhabiting the underground fresh waters. The fishes, blind or partially blind, living in the depths of the ocean bordering the American continents, are as follows: 1. Ipnops Murrayi Günther lives at depths varying from 955 fathoms to 2,158 and has the very wide distribution suggested by the localities from which specimens have been secured--viz., off the coast of Brazil, near Tristan da Cumba, near Celebes, latitude 24° 36′ north, longitude 84° 51′ west, and off Bequia. This is the only vertebrate in which no vestige of an eye has been found. Ipnops stands alone in a family. 2. The Brotulidæ have several members blind or with very much reduced eyes in various parts of the globe. Aphyonus mollis G. and B., 955 fathoms, and Alexeterion parfaiti Vaillant, 5,005 metres, are the only ones found in the neighborhood of America. 3. The Lophiidæ are represented by Mancalias Schufeldtii Gill, from a depth of 372 fathoms. Other blind species are found in foreign waters, while others with small eyes are found in American waters. The majority of deep-sea fishes have well-developed eyes. The shore fishes have their blind representative in Typhlogobius californiensis St., which lives under rocks between tide water on the coast of southern and Lower California. I have elsewhere described the habits of this form. In the fresh-water caves of Cuba two blind fishes--Stygicola denta Poey and Lucifuga subterraneus Poey--have been found. Their relatives live in the ocean, Brotula barbata in Cuban waters; some of the others are blind and inhabitants of deep water.