MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 127 



carry olfactory organs. In C. affinis I have counted as many as thirty-three segments in the flagellum, nineteen with 

 olfactory setas. A moderate-sized C. blandingii from New Jersey reveals about fifty segments, twenty-nine of them 

 provided with olfactory setaa. It thus appears that Professor Wright's conclusion, that the number of antennulary 

 segments aud olfactory organs is increased in the blind species, is not supported by the facts. It is noteworthy, how- 

 ever, that the olfactory setaa of C. pellueidus are longer than in most species of Cambarus. In a specimen of C. hamu 

 lattis, the other blind cave species, there are thirty segments in the outer flagellum of the antennule, and the olfac- 

 tory set:e are long, as in C. jpellucidus. 



The blind 'fish of Mammoth. Cave (Amblyopsis spelmus), as is well known, is provided with 

 tactile papillae arranged in ridges on the sides and front of the head, as originally described by 

 Tellkampf and by Wyman, and more fully by Leydig, who has, with other details, given a good 

 figure of the head of this fish. Tellkampf regarded these papillae " as without doubt increasing 

 the tactile sense," and Prof. R. R. Wright suggests that "the want of sight in the blind-fish is 

 compensated for by the development of the tactile ridges."* The extreme timidity and caution 

 of the fish have been observed by Tellkampf and by Dr. Sloan. 



Similar ridges, with a like arrangement, are described by Prof. F. W. Putnam and figured by 

 him as existing on the head of TypMichthys subterraneus Girard; so that the two genera are alike 

 in this respect, t 



What little is known of the habits of the blind-fish is embraced in the following extracts from 

 Tellkampf | and in the subjoined letter from Dr. Sloan : 



The blind-fish is found solitary and is very difficult to be caught, since it requires the greatest caution to bring 

 the net beneath them without driving them away. At the slighest motion of the water they dart off a short distance 

 and usually stop. Then is the time to follow them rapidly with a net and lift them out of the water. They are 

 mostly found near stones or rocks which lie upon the bottom, but seldom near the surface of the water (p. 86). 



Again, on page 92, he writes: 



During my stay at Mammoth Cave I observed that the Amblyopsis, the black-fish [which we suppose to be the 

 Chologaster], and the crawfish remained motionless while I moved a burning lamp around them, but that they were 

 disturbed by a slight motion of the water, proving that the light made no impression upon their optic nerves, while 

 their sense of touch was acute. 



The following letter, from Dr. John Sloan, dated New Albany, Iudiana, February 11, 1883, 

 gives an excellent account of the habits and sensibility to light and sound of the Amblyopsis 

 spelceus : 



From 1866 to 1875 I made many explorations of caves in southern Indiana, and frequently had considerable 

 numbers iu my aquarium of the larger blind-fish (Amblyopsis spelceus). If you will look at the Report of the Geolog- 

 ical Survey of Indiana you will see a notice of Lost River, a considerable stream, which disappears from the channel 

 at several points 2 miles from Orleans, Orange county, and pursues its course underground for more than 7 miles. 

 There are numerous sink-holes and no surface streams in that neighborhood. 



There are no wells which furnish water in that country except those that strike some stream or body of water 

 beneath this stratum, aud blind-fish are frequently drawn up in the buckets. 



There is a cave 4 miles west of Orleans, which extends to this subterranean channel of Lost River, in which the 

 Amblyopsis are quite abundant. Soon after the publication of Professor Cope's article ou the blind-fish of Wyandotte 

 Cave I visited it with several of my friends for the purpose of testing their sensibility to light and sound. In a pool 

 10 by 15 feet, varying from a few inches on three sides to 4 feet on the other, there were large numbers of them. I 

 tested their hearing by hallooing, clapping my hands, and striking my tin bucket when they were iu easy reach and 

 near the surface. In no instance did they change their course or notice the souud. We carried our lighted candles 

 within a few inches of them when near the surface, but they seemed wholly insensible to their existence; but if a 

 drop of tallow fell in the water near them they would swim rapidly away. I brought home twelve, as many as could 

 live in my bucket. Of these twelve caught in September none died until next June, when the water became warmed 

 to near 70°, when several of them died with tetania convulsions (f). I put the remainder in my cellar, where the tempera- 

 ture ranged from 45° to 60°, where one, "Blind Tom," lived eleven months, inakiug twenty months of existence with- 

 out having taken any visible food. While in my aquarium they manifested total indifference to light and sound. 

 Some of them would strike eagerly at any small body thrown in the water near them, rarely missed it, and in a very 

 short time ejected it from their mouths with considerable force. I tried to feed them often with bits of meat and fish 

 worms, but they retained nothing. On one occasion I missed a small one and found his tail projecting from the mouth 

 of a larger one; I captured and released him. They manifest great sensibility on the back and sides to any approach- 

 ing body, but do not notice an attack from below. It is not possible to capture one by a side sweep of a net, but by 

 passing it under him a considerable distance below and bringing it up slowly there is no difficulty in taking them- 



* American Naturalist, xviii, 272, 1884. 

 t American Naturalist, February, 1872. 

 t New York Journal of Medicine, July, 1845. 



