412 
Proceedings of the Poycd Society 
5. Abstract of Eeport on the “ Porcupine ” Tunicata. 
By Professor W. A. Herdman. 
This paper deals only with the Ascidioe Simpliees collected 
during the cruises of the “Porcupine” in the summers of 1868- 
1870. The Asciidce Compositoe will be worked up along with the 
“ Challenger ” forms, and will appear in the second part of the 
Eeport upon the Tunicata of that expedition. 
Eleven species of simple Ascidians were found in the “ Por- 
cupine” collection. There are no Clavelinidse, but the other three 
families are represented — the Ascidiidse by three species, the 
Cynthiidae by five species, and the Molgulidae by three species. 
Three species (all belonging to the genus Polycarpa) seem new to 
science ; the remaining eight are most of them common British 
species. Some of them, however, possess an interest apart from 
their morphological peculiarities on account of the localities and 
depths from which they were obtained. For example, several of 
the stations are in localities of which the Ascidian fauna had never 
been investigated, and the depths of which exceed 100 fathoms. 
Styela grossularia, van Beneden, a common British species, which 
is usually regarded as a littoral or shallow-water form, was obtained 
in the North Atlantic between Lewis and the Faroe Islands (Station 
54), at a depth of 363 fathoms ! 
6. Arrangement of the Metals in an Electro-Frictional Scale. 
By A. Macfarlane, D.Sc. 
While, in recent years, the progress of the science of electricity 
has been very rapid, few investigations have been made in the old 
province of frictional electricity. It cannot be doubted, however, 
that the laws connecting electricity with friction, and with the 
nature of the substances rubbed, are of great importance j and the 
acquisition of more detailed knowledge in this department may 
throw some light on the still imperfect theory of the voltaic cell. 
Several electricians have expressed an opinion that the development 
of electricity by friction is only a modification of the develupmei.t 
of electricity by contact — that friction is contact in which the 
