of Edinbi irgh, Session 1880-81. 217 
alimentary canal. They occupy one side, while on the other is a 
bulky granular structure, which probably represents the male 
element. The ova occur in great numbers amongst the tentacles. 
No observation of note was made on the nervous system. 
The species forms a somewhat tough hyaline tube (evidently a 
secretion of the hypoderm) for itself in the sand, as in other forms 
having a similar habitat. In this coating sand-grains often occur, 
but they do not form a regular layer. Even the most translucent 
portions of the tube show many minute sponge spicules, diatomes, 
and fragments of silex. 
This form of Phoronis deviates considerably from those previously 
described andfrom the ordinary Gephyreans. If, indeed, the branchial 
skeleton supporting the vessels were thrown in, and arranged at the 
side of the anterior region of the body, so that the water would enter 
by lateral slits, to aerate the circulating fluid, and the digestive canal 
enlarged and attached as a single tube to the body-wall, a form 
resembling Balanoglossus would be indicated. In both, as they 
exist, the food passes along the branchial apparatus before reaching 
the alimentary canal. The branchial arrangement and the flexure 
of the intestine also show certain analogies with the condition in the 
Polyzoa. 
2. Additional Kesearches on the Structure of the Paloeoniscidoe 
and Platysomidce. By Dr K. H. Traquair. 
3. Note on the Heating produced by Compression. 
By Professor Tait. 
By the help of an iron-copper junction introduced into the 
smaller compression apparatus lately described to the Society, I 
have examined for a number of substances the rise of temperature 
produced by a sudden application of great pressure, and the corre- 
sponding fall of temperature when the pressure was very suddenly 
relaxed. The copper-iron circuit is, however, too little sensitive for 
very accurate measurements ; as, from the nature of the apparatus, 
the wires must be so thin as to have considerable resistance, and the 
thermoelectric power of the combination is not large. I hope soon 
to have wires of cobalt, which (associated with iron) will give 
