PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 121 



aud all of tliem completed the cliange into tlie Amhlystoma inside of 

 six weeks, while I have had Init three changes of those kept iu the cauf 

 (sixty of them) in three months. During that time they have not been 

 fed at all. The Siredon mexicanus is said to never undergo the trans- 

 formation in its home, and Professor Marsh doubts that it ever makes 

 it here. This doubt I can put at rest. They do make the change here, 

 and in large numbers. During the latter part of the month of July 

 and the entire month of August, if the day is rainy or misty, they come 

 from the lake in to the shore in large numbers, and secrete themselves 

 under some piece of wood or rock where they can keep moist. Some- 

 times they venture out in a shower, and the sun catches them before 

 they can obtain shelter either in the lake or under cover, and in a few 

 minutes kills them. They can be found dried hard anywhere about the 

 lake, on the shore or in the grass. While catching Siredon I have seen 

 and caught a number of Amhlystoma in the lake, with the metamor- 

 phosis, as far as I could see, as complete as those we find half a mile 

 from the lake. They cover the ground by thousands during a warm 

 summer rain, coming from every conceivable place where they could 

 have found shelter, from under rocks, boards, old ties, and out of 

 gopher holes. I have a cat that eats them greedily. She has fished 

 several out of jars on the table and devoured them during the night 

 when there was no one to watch her ; and I am told by a resident that 

 the numerous skunks that live around the lake live principally on them. 

 They are of two colors, a blackish green and a yellowish green color. I 

 have had two of the blackish green complete the change in sequence, 

 while one of the yellowish green was completing it under the same cir- 

 cumstances of change of water and food.' I think this will be found to 

 be the result iu all similar cases. I have caught them in all stages of 

 growth and in all stages of their changes into the Amhlystoma state. 

 During the months of July and August they lie close to the shore of 

 the lake, where it is shallow ; but after the first frost they disappear 

 completely, or at least I have never been able to find them. I think 

 they must bury themselves in the mud at the bottom of the lake, as I 

 have stirred up the grass often and have not seen them issue from it. 



ON THE DESTRUIITIOIV OF FI.«iII BV POISONOUS M ATER IX THE 



CiUI.F OF MEXatO. 



By JOSEPH \. PORTER, Assistant SMigcoii, U. S. A. 



United States Army Hospital, 

 Office of Post Surgeon, Key West Barracks, Fla., 



January 21, 1879. 



Professor : I forward you to-day by express a small box containing 



a quart of Gulf water, procured 20 miles from this port. I enclose you 



a slip of paper taken from the "Key of the Gulf," a local of this place, 



which in its turn clipped it from the "Forest and Stream." It seems to be 



