LUBBOCK ON THE ANCIENT SHELL-MOUNDS OE SCOTLAND. 415 
39. At all events it must be generally admitted that we have 
many instances in the sub-kingdom Protozoa of the effective per¬ 
formance of the functions of assimilation, of respiration, and of 
automatic motion in beings formed of homogeneous sarcode alone, 
without the differentiation of any special tissue or organ. Conse¬ 
quently, a layer of this substance, investing the nascent embryo of a 
higher organism, may answer the same purpose, though perhaps in 
an inferior degree, as if the germ were provided with special pro¬ 
visional organs for the performance of these functions. 
40. I have already stated that Bipinnaria consists essentially of 
two parts, an absorbent, assimilative, and locomotive, sarcode zooid; 
and a ciliated sac, containing a special nutrient fluid, elaborated by 
the sarcode zooid, and in immediate connection with the ambulacral 
vascular system of the Echinoderm embryo. In Bipinnaria (§§ 6—18) 
the special organs of nutrition and locomotion of the pseudembryo 
are fully developed, and the vascular sac is comparatively insignifi¬ 
cant. In Brachiolaria (§§ 19—21) both sets of organs are well de¬ 
veloped, and they are nearly balanced in bulk. In Asteracanthion 
violaceus (§§ 22—27) the organs and appendages special to the 
pseudembryo, the pseudostome and the pseudocele, are in abeyance, 
and the zooid is reduced to a sheet of sarcode investing the germ, 
and a peculiar modification of the ciliated sac. 
In Bteraster Militants (§ 35) the zooid is likewise reduced to an 
investing sheet of sarcode, a large portion of the germ-mass being 
converted immediately into the embryo, but the ciliated sac is gone, 
and we have once more the provisional mouth and alimentary canal 
imbedded in the sarcode wall. 
Unfortunately the observations on the “ Vermiform larva” of 
Muller are as yet too imperfect to admit of any satisfactory deter¬ 
mination of its relations. 
XLV—A Visit to the Ancient Shell-Mounds of Scotland. 
By John Lubbock, Esq. Pres. Ethn. Soc. E.E.S. &c. &c. 
In our April number we mentioned that the Bev. George Gordon 
of Birnie, near Elgin, had found on the shores of the Moray Erith 
several shell-mounds, more or less resembling the kjokkenmoddings 
of Denmark. Since that time I have been down to Scotland, in 
order to visit these shell-mounds, and Mr. Gordon has had the kind¬ 
ness to show me all those which are as yet known to him. He also 
pointed out to me the remains of a lake dwelling, discovered by Dr. 
Grigor of Nairn, in the “ Loch of the Clans,” about five miles from 
that town. This little lake has been partially drained, and the re¬ 
mains of the piles are thus laid dry; the ground was still, however, at 
the time of my visit, too marshy to permit a satisfactory examination 
