76 BLIND VERTEBRATES AND THEIR EYES. 



Chologaster agassizii Putnam. Plate 6. 



Chologaster agassizii, Putnam, Amer. Nat., VI, 1872, p. 22, well at Lebanon, Tenn. ; Mammoth Cave, Kv. — 

 Jordan, Rept. Geol. Nat. Res. of Ind., VI, 1874 (1875), p. 218 (reference to Putnam's specimens). — Hay, 

 Geol. and Nat. Res. of Ind., xix, 1894, p. 234. — Jordan and Evermann, Fishes North and Mid. Amer., 1S96, 

 1, p. 704. — Eigenmann, Proc. Ind. Acad. Sci., 1897 (189S), p. 230; Eyes of the Blind Vertebrates of N. A., 

 Archiv f. Kntwickelungsmech., VIII, 1899, p. 546; Proc. Ind. Acad. Sci., 1898 (1899), pp. 239, 251; Marine 

 Biological Lectures, 1899 (1900), p. 113. 



Chologaster agassizii Putnam is known only from Lebanon, Tennessee, and 

 caves about Mammoth Cave. I have taken it in the Styx in Mammoth Cave and 

 in Cedar Sinks, near Mammoth. I found the Chologaster in only one locality in 

 Mammoth Cave. A short distance after descending the corkscrew the Styx appears 

 on the right. On one visit Chologaster was abundant in and around the remains 

 of an old boat, but I secured only a few small specimens on account of their agility 

 and the easily roiled water. They were much more alert than the blind members of 

 the family and made quickly for the lower edge of the wall of the cave, below 

 which many of them escaped. On a subsequent visit the locality had been quite 

 modified, and I secured even fewer specimens than before. 



Cedar Sinks, the other locality from which I secured Chologaster agassizii, is a 

 highly interesting region. It lies several miles from Mammoth Cave and is 

 reached over a rough road leading, without modifications from the engineer, up and 

 down the steep slopes of the interminable sink holes of the region. Cedar Sinks 

 was formed by the caving in of the roof of an enormous cave room. The vertical 

 walls of the room are still standing. I have been told the bottom of the sink 

 embraces about 4 acres. In the bottom are 2 funnel-shaped depressions holding 

 water. The walls of the funnels are so steep that it is just possible to climb out if 

 one has been foolish enough to slide down. At the base of the highest rock bound- 

 ing the sink are two openings. One leads to an extensive underground stream 

 which can be followed a very restricted distance ; the other, to a stream and cave 

 which must be quite extensive, judging from the inflow of air at the time of one of 

 my visits. Small pools or streams in one of the entrance galleries yielded a few 

 specimens of Chologaster. 



THE COLOR OF THE AM BLYOPSID/E. 



The three species of Chologaster are colored with varying intensity from C. 

 comutus, which is darkest, to C. agassizii in Mammoth Cave, in which the 

 color is faintest. The color cells are in all cases arranged in a definite pattern. 

 This is determined by the underlying muscles. The pattern consists of three lon- 

 gitudinal bands on the sides following the line where the muscle segments are 

 angularly bent and cross stripes along the line separating successive segments 

 (plate 6, upper figures). 



The lower side of the head and the abdomen of Chologaster papilliferus are 

 sparingly pigmented and translucent. The underlying liver and gills give the 

 parts a rosy tinge. On the sides and top of the head pigment is abundant. There 

 is a more densely pigmented area extending along the middle of the back, begin- 

 ning as a narrow stripe at the nape and widening to the dorsal fin behind, where it 

 occupies the entire back. On the sides are 3 narrow stripes, which, owing to the 

 accumulation of pigment in 2 layers, are quite dark. Each stripe has a lighter 

 central band, widest at the middle of the sides. A light band, without the con- 

 spicuous bordering dark stripes, runs along the middle of the belly. The sides are 

 thickly covered with a layer of pigment, leaving usually colorless lines where con- 



