108 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
Blind eel in a cave in the Tonga Islands. —Dr. R. W. Coppinger, during the cruise of the Alert, 
explored a system of caves ou the south side of Tougatabu. “ In the floor of the chamber were 
deep pools of water probably communicating with the sea, and said to be tenanted by a species 
of blind eel about 2 feet long, which we were told the natives sometimes caught with hook and 
line and fed upon” (p. 176). Unfortunately Dr. Coppinger failed to obtain a specimen. 
Class BATRACHIA. 
Cceoilia, Siphonopa, and Epicrium. “Eyes only visible through the skin as small specks” (Claus’s Zoology, 
English trans., ii, 187). 
Proteus anguineus Laur, Subterranean waters of Carniola and Dalmatia. Eyes rudimentary. 
Class REPTILIA. 
Family Typhlopidse. 
Typhlops sp. “ The small eyes are concealed each under a plate always larger than the eye itself. The latter 
is sometimes invisible, either because the loose epidermis becomes opaque, or because the visual organ is 
too small and too imperfect to be seen from without” (Jan, quoted by Duchamp, 40). 
Family Calamariidae. 
Typhlogeophis Irevis Gunther. Possesses no external rudiments of eyes (Gunther, Proo, Zoological Soc., 
London, January 14, 1879). 
Mr. G. A. Boulanger kindly informs me that the following Lacertilia are “ blind:” the species 
of the families Amphisbsenidae, Anelytropidse, and Dibamidse. 
Class MAMMALIA. 
Order Insect ivora. 
Talpa coxa Linn. Blind mole; eyelids closed. 
Order Rodentia. 
Spalax typhlus Pallas. Blind mouse. “ Eyes rudimentary.” 
Ctenomys traziliensis. (See Darwin’s “ Origin of Species.” *) 
Batliyergus. South Africa. 
Siplmus. Eastern Asia. Eyes like those of moles. 
VIII.—ANATOMY OF THE BRAIN AND EYES (WHEN PARTLY DEVELOPED) OF CERTAIN 
BLIND ARTHROPODS. 
THE BRAIN OF THE EYELESS FORM C/EClDO’lLEA.t 
It is a matter of great interest to know just what, if any, changes take place in the brain or 
nerve-centers of the head of the eyeless forms related to Asellus; whether the modification is 
confined to the external parts of the eye, or to the optic lobes and nerves alone. 
As previously stated, a blind Asellus-like form is abundant in the brooks and pools of Mam¬ 
moth and other caves in Kentucky and Indiana, as well as in the wells of the cavernous and adjacent 
regions. The foregoing observations on the brain and eyes of the common Asellus of our brooks 
and ponds were made to afford a basis of comparison with the similar parts in the eyeless form. 
Csecklotsea in its external shape is seen to be a depauperate Asellus, with the body, however, 
much longer and slenderer than in the eyed form, and with slenderer appendages. It is not usually 
* Dr. R. W. Coppinger, in the cruise of tbe Alert (1883), says that, contrary to Darwin’s opinion that the tucutuco 
(Ctenomys) never comes to the surface, “the little rodents were commonly to be seen near their holes about the time 
of dusk, and that they invariably retreated to the burrows on the near approach of a human being ” (p, 27). In a 
subsequent page he speaks of seeing one himself. 
t This section is in part reprinted from the author’s paper “ On the structure of the brain of the sessile-eyed 
Crustacea.” Memoirs Nat. Acad. Sci., iii, 1885. 
