258 UNIVERSITY OF COLORADO STUDIES 



of the State University. Its altitude is about 8,889 ^^^t; the average 

 mean temperature for July about 60 degrees F. In this small hamlet 

 a mountain Laboratory for the study of field biology is maintained 

 every summer by the University. 



When first noticed on June 16, 1909, the salamander larvae were 

 found scattered all along the western and southern bank of Park Lake. 

 (See Fig. 2.) None at all were found along the eastern and northern 

 shores. Along these shores there is little grass and few stones under 

 which they could seek shelter. Here, also, the lake bottom recedes 

 gently away to deeper parts. On the sides where the larvae were 

 found the deeper water is close in and there are numerous inlets into 

 marshy places where plenty of grass covering can be found. 



The larvae on the first day of observation and for several days 

 following were distributed regularly along these two shores (western 

 and southern) and there was no evidence of congregating in bunches. 

 As yet there was no pond scum (Spirogyra) present on the lake. 

 The larvae were generally found lying with their heads under the 

 protection of a rock. When disturbed, they always swam away to 

 deeper water. Those whose movements could be followed always 

 returned to shallow water near to the place where they left it. The 

 larvae at this time were very active and on several occasions when 

 taken would leap out of a net. This action was brought about by 

 the use of the tail rather than by any movement of the limbs. When 

 in motion, while the fore Hmbs might appear to aid the action some- 

 what, the hind limbs were extended backward in the direction of the 

 tail and were practically useless except as a more perfect means of 

 balancing in the water. 



On June 20, 1909, while a few were scattered along the west and 

 south of the lake, in one place they were present in a shoal. This was 

 a little inlet with an island dividing it into two parts. Back from the 

 shore a little way it was broken up into numerous little bodies of 

 water which projected farther into the land. Two days before this 

 time pond scum (Spirogyra) became prominent. In fact, this little 

 inlet was entirely covered with it. Here the larvae were present 

 in such countless numbers that they cut the water into ripples, going 



