100 THE HAMILTON ASSOCIATION. 
evolution of the fossil, Amerzcan Brachiopoda, has been already 
clearly and most convincingly shown by Dr. Beecher, Professor 
Schuchert, and others. We may expect the evolution of the 
Conchifers to naturally follow. The tendancy at present is to 
form new genera or species from what may prove to be mere 
varieties. You will find the pallial impression in the right 
valve of the Conchifer. 
ANATINID#. 
The Anatina of Lamark, sometimes called the ‘‘ Duck” or 
‘*Tantern Shell,” has the muscular impression faint, thin, 
usually in equi-valve, possessing little beauty. It, or rather 
the sub-genera, has some interest in the eyes of the Palzontolo- 
gist, since several fossil forms have been—rightly or wrongly— 
classed under the head from the Paleozoic (Devonian) upwards. 
It has been noticed while in the living Anatina the ligament is ex- 
ternal, cartilage internal. In Pholadomya, etc., we have the exter- 
nal ligament only. This objection may be of little importance. 
It was supposed that one member of the family was a boring 
Mollusc (Thracia pubescens, Britain), but a closer investigation 
proved it only occupied the burrows made by others, or perhaps 
when young was accidentally conveyed into empty burrows of 
Saxicava. | already mentioned at Anticosti ‘‘ Mytilus Edulis 
may be noticed (small specimens chiefly) concealed in similar 
crevices of limestone rocks. 
In the foregoing the writer may have referred to a few 
shells not found in our collection here, and trusts he has not 
omitted any important family. 
