123 
of Edinburgh, Session 1875-76. 
thermo-electric curve at a high temperature. For this an arrange- 
ment was used similar to that employed for the iron wire in the 
experiments formerly described (“ Proc. R. S. E.” 1874-75, pp. 
629-631). But no results were obtained, owing to the breaking 
of the nickel ribbon when exposed to the great heat of the white hot 
cylinder. 
The following Gentlemen were elected Fellows of the 
Society: — 
William Skinner, Esq. 
J. Ballantyne Hannay, Esq. 
Peter Denny, Esq. 
Monday , 21 st February 1876. 
Sir WILLIAM THOMSON, President, in the Chair. 
The following communications were read : — 
1. On the Structure of the Body-wall in the Spionidse. By 
W. C. MTntosh. 
In regard to external form, Nerine foliosa , Sars, is generally taken 
as the type of the family, and therefore it may be selected for 
structural examination in the first instance. Anteriorly the pointed 
snout is completed by the intricate interlacing of the muscular 
fibres beneath specially thickened cuticular and hypodermic layers. 
As soon as the body-wall assumes a rounded form, a layer of circular 
and oblique muscular fibres occurs beneath the hypoderm, the 
majority having the latter (i.e., the oblique) direction. In the 
centre of the area the oesophagus is suspended by strong muscular 
bundles (the most conspicuous of which are vertical) passing from 
the hypodermic basement-layer in the middle line superiorly to be 
attached to the oesophagal wall. A second series, as they descend 
to their insertion at the ventral surface, give lateral support to the 
tube; while a third group interlace in a complex manner, and, with 
the blood-vessels, fill up the space between the oesophagus and the 
wall of the body. 
Toward the posterior part of the head is found — on the dorsal 
surface — a slight hypodermic prominence, which indicates the 
position of the central ganglia of the nervous system ; the latter 
