1878.] Rambles Round San Francisco. 353. 
wall-flower, Cheiranthus capitatus Dougl., and the pretty red rock- 
cress, Arabis blepharophylla, but now, the rains just over, we only 
find green leaves. 
In a hollow between the hills, where a tiny rillet is bordered 
with willows and dwarf shrubs of the blue ceanothus (C. thyrsi- 
florus), we see a flock of blue-birds, and pick up several red- 
bellied salamanders (Diemyctylus ma as they awkwardly 
sprawl among the wet herbage. 
. Descending to the beach at the fort we pick up among the 
débris cast up by the tide two species of those little jumping 
amphipodous crustaceans commonly called sand-hoppers, one 
kind (Orchestia californiensis Dana) is stoutly made, and is not 
found except near high tide level where it burrows in the sand in 
great numbers and hides beneath the wet débris; but the other 
species (QO. żraskiana St.) is more terrestrial in its habits, and may 
be found under heaps of dried grass and straw, dry horse-drop- 
pings, etc., at some distance from the beach. 
On the under sides of the flat stones, wriggling along the wet 
surface and jumping actively when touched, we find a much 
smaller amphipod, less than half an inch in length, some of these 
we place in a bottle of sea-water, and on examination under the 
microscope at home are struck with the beautiful plumes of hairs 
which adorn the under side of the joints of the antennæ, and 
know that it is A//orchestes plumulosus Sb. 
Along the edge of the rising tide we pick up two small jelly- 
fishes. They have little beauty and apparently little life when 
picked up, but after a few minutes in a large bottle of sea-water 
they begin to expand and contract their bells, a circlet of bright 
purple spots (ocelli) becomes conspicuous around the margin of 
the bell, and the tentacles all contracted when we pick them up, 
lengthen out until they reach from two to three times the height 
of the bell, which is about an inch. It is Polyorchis penicillata 
A. Agass., one of the loveliest of jelly-fishes. Large specimens of 
Aurelia labiata, a Discophorous medusa fully a foot across, with 
large purplish ovaries showing through the transparent bell, are 
floating upon the tide or stranded on the shore. 
Leaving the shore we walk along the edge of a large pool in 
the salt-marsh between the Presidio and the sea; here a large flock 
| of gulls is swimming; there are two species, one is the common 
2 yellow-billed Larus eccidedalis, but the other, conspicuous from 
