CORRESP ONDENCE. 



109 



in the thousands of species of fishes, do 

 not obtain iu the case of the mud-minnow 

 The membrane is dense, the rays numerous 

 and strong, and the fin is held at a right 

 angle with the body when the fish is in an 

 horizontal position, and nearly so whatever 

 other position may be assumed. The ven 

 tral fins, likewise stiff and strongly rayed, 

 when the fish is swimming, are not much 

 used, but as soon as the animal comes to a 

 rest they are spread out, and, with the pecto- 

 ral fins, now stifi" and motionless, they form 

 four legs that support the body, just as a 

 salamander does. Indeed, the likeness goes 

 further, and the body is curved frequently 

 when at rest, and remains so ; the head 

 turned to the right or left, the tail in the 

 opposite direction. No one can fail to see 

 the salamandrine appearance of this fish in 

 this position. Now, if we follow up the 

 habits of the fish, what unfish-like if I 

 may use the expression habit other than 

 this can we detect ? Knowing its predilec- 

 tion for thick and muddy waters, I find it 

 not only conceals itself in the mud during 

 the summer, but it deeply embeds itself 

 and regularly hibernates ; and in times of 

 drought will live, as I have determined by 

 experiment, twenty-eight days, in stiff mud, 

 far less moist than the usual ditch-bottom, 

 during a dry summer. This must be recol- 

 lected in connection with its salamandrine 

 aspects when in water. Again, by experi- 

 ment, I find that this minnow, out of water, 

 will outlive all other fishes of our streams, 

 except the eel and possibly the catfish. My 

 experiments showed it outlived a common 

 sunfish just 500 per cent. ; a roach, 1,500 per 

 cent. ; and a catfish and mud-minnow, taken 

 from the water together, and kept thirty- 

 five minutes in the air, were both very sick 

 when replaced in the aquanum. The cat- 

 fish revived in three minutes ; the minnow 

 in eleven. This unusual ability of retain- 

 ing life out of its natural conditions and 

 surroundings is just such a peculiarity as 

 one might look for, in this species, having 

 once noticed the peculiarity of the fins I 

 have mentioned. To-day, however, I no- 

 ticed for the first time a movement on the 



part of the mud-minnows, in my aquarium, 

 never before detected, and which made the 

 fins more leg-like than ever. Two speci- 

 mens were resting, as we have described, 

 on the tips of the pectoral and ventral fins. 

 Coming near them suddenly, one, and then 

 the other, moved several " steps," i. e., they 

 gave their fins a leg-like motion, which left 



( ( ( ( 

 faint impressions, thus ( ( ( ( upon 

 the sand. I had never seen such fin-move- 

 ments on the part of this fish before, nor 

 have I since, although for a week past I 

 have carefully watched them. 



Taking, now, into consideration the hab- 

 it of resting on the tips of the fins ; of giving 

 the body a serpentine position, often main- 

 tained for many minutes ; of burrowing in 

 the mud ; and able to withstand the atmos- 

 phere for a remarkable length of time ; to 

 which I think I may add walking on its 

 fins may we not see in all these a " leaf- 

 bud," as it were, which in the far future 

 will expand into an air-breathing, salaman- 

 drine animal ? 



Have we here really caught a faint 

 glimpse of evolution ? 



Since the above was written, I have re- 

 ceived and read Schmidt's "Descent and 

 Darwinism." On page 130 he quotes from 

 Lyell, as follows : " In a word, the move- 

 ment of the inorganic world is obvious and 

 palpable, and might be likened to the min- 

 ute-hand of a clock, the progress of which 

 can be seen and heard ; whereas the fluctua- 

 tions of the living creation are nearly invisi- 

 ble^ and resemble the motion of the hour- 

 hand of a timepiece. It is only by watching 

 it attentively for some time, and comparing 

 its relative position after an interval, that we 

 can prove the reality of its motion.'''' This 

 quotation is the same idea far more lucidly 

 expressed ; and, had I been aware of its ex- 

 istence, my remarks would have remained 

 unwritten. As it is, are they not a confirma- 

 tion of my belief that evolution is, after a 

 manner, visible, and do we not find an in- 

 stance of this in the mud-minnow ? 



Charles C. Abbott, M. D. 

 Peospkct Hill, Trenton, N. J., March 16, 1875. 



