1878. ] Rambles Round Sah Francisco. 347 
which is separated from the muscular layer by a wide interspace, 
the muscular coat uc. C being attached to the connective only 
underneath the furrows, where there is also a single bend of 
longitudinal muscles, Z, placed outside the transverse muscles. 
Finally in the rectum, as shown in a transverse section, the 
epithelial cells are differentiated into two kinds, larger ones of 
the ordinary form, and smaller ones which lie higher up and pre- 
sent a circular outline. In’ vertebrates this differentiation of 
adjacent epithelial cells is carried to a great extent, and is espe- 
cially connected with the development of glands; but the discus- 
sion of these is foreign to our present purpose. 
In conclusion I will give a summary of our observations: 
Animals are built up of cells; each cell consists of a protoplas- 
matic body, a nucleus and a nucleolus; the cells are often grouped 
together so as to form a single continuous layer, which is called 
an epithelium; the free surface of such a layer is often covered by 
a thickened membrane, the cuticula, which is formed by the under- 
lying cells. The cells of an epithelium may be modified, first as 
to size, second as to form, third, character of the cuticula, fourth, 
position, size,and shape of the nucleus and nucleolus, fifth, presence 
of granules or pigment, and sixth, differentiation of adjacent cells 
into two or more kinds. The epithelium may be modified by the 
formation of folds and pits of various forms. 
oim 
RAMBLES ROUND SAN FRANCISCO. 
BY W. N. LOCKINGTON. 
NO. I. THE OCEAN BEACH. 
HE peninsula of San Francisco does not offer a very inviting 
field to the naturalist. A wilderness of rocky hills and sand- 
dunes, bearing no vegetation larger than a scrub oak, and swept 
by the winds and fogs of the great ocean, it lies, between the 
Pacific and the Bay of San Francisco, a bare and naked spot in 
the long wooded coast-line of California. 
Yet, here as elsewhere, he who seeks with willing and educated 
eyes, will not fail to find much to interest him. The sand-dunes, 
the cliffs that border ocean and bay, and the rounded sandstone 
hills have each their special flora; many species of gulls, ducks 
and divers, herons, pelicans and cormorants visit the bay and the 
