1878. ] Rambles Round San Francisco. 349 
drop him, or he will drop off his own tail and leave you a spoiled 
specimen. The Scelepori are not so fond of throwing off their 
tails, nor nearly so apt to bite, but in summer time when they are 
` active they are exceedingly hard to catch. They are not called 
swifts without reason. 
What is the color of a tree-frog? Green for the most part, 
certainly, yet it varies greatly. The black marks upon the back 
are very distinct in some, quite faint in others, and one of our 
specimens is brownish, while another inclines to yellow. These 
fellows we have caught under the bushes are, in one sense, not so 
“green” as those we will find among the leaves at a more 
advanced season. 
But our low bush furnishes us with insect as well as with rep- 
tile life. It literally swarms with “squash-bugs,” big black milli- 
pedes (Fulus) lie coiled among the decaying leaves, a long bright- 
red Scolopendra hurries away from our invading hand, and hunt- 
ing spiders run to and fro in hot haste. 
We are now onarising ground at the edge of the Presidio 
reservation. Below us, in a little valley encircled by hills, lies a 
small fresh-water lake known as Mountain Lake, a line of shrubs 
beyond this marks the course of the stream which runs thence to 
the ocean, and the view is closed by the cliff-encircled bay outside 
the Golden Gate, forming the entrance to the harbor of San 
Francisco, Away on the farther side of the bay is the white 
lighthouse of Point Bonita, and oceanward a line of breakers 
marks the dreaded bar. 
We hasten down to the lake, hoping to find there, as we have 
found before, numerous specimens of the fresh-water snails of the 
genera Limnophysa, Physa and Helisoma, as well as the tiny flat 
Gyraulus vermicularis Gld. But we have forgotten the thirty 
inches of rain that have fallen since we visited the spot in Sep- 
tember last. The lake that was then so low that we could explore 
much of its bed, and so clear that we could see the bottom, is 
now a broad sheet of turbid water, in which the shell-fish are lost 
to sight. The spot where we picked up the flat-whorled Helisoma 
in shallow water, full of confervz is now far from the shore, and 
the beach, once strewed with the shells of the fresh-water clam 
(Anodonta wallamatensis, sweet name this), is now lake bottom 
again, 
The yellow water-lilies (Nuphar advena) whose tops and mas- 3 
