534 RELATIONS OF ANOMIA. 
by external characters. The whales among fishes, the barnacles 
among mollusks, were only some of the many blunders made by 
this superficial way of comparison. And now after the structure 
of Brachiopods is well known, and all admit the valves to be dor- 
sal and ventral, while the valves of Anomia are right and left, 
and after the splendid memoirs of Lacaze-Duthiers on the anatomy 
of Anomia has shown that the nearest relations are with the oyster 
and pecten, there are still several zoologists who vaguely imagine 
that some sort of relationship exists between Terebratula and 
Anomia. This brief communication is made to settle the ques- 
tion with those who never care to go more than shell deep in the 
subject, for unfortunately the author had only the empty shells to 
work upon. It will also verify the statement made by Forbes and 
Hanley in their standard work on the British Mollusca, where the 
shelly plug which escapes from the sinus in the flat valve to hold 
the body to its base of attachment is compared to a byssus. 
They say ‘‘ When the very young fry of this genus shall have been 
carefully observed, we believe they will be found spinning a 
byssus, which passing through this sinus fixes the shell in the first 
instance, before a portion of it becomes attached, eventually be- 
comes detached with a part of the adductor muscle and forms 
the opercular process.” Lacaze-Duthiers in his examination of the 
adult form refers to these statements and oe his belief in 
their correctness. 
In examining some sea-weed éotlectel by a friend last spring 
I found a lot of the young of Anomia. In these the sinus was 
not closed, but open toward the anterior margin. The nucleus 
presented an elongate oval shell larger behind ; the beaks nearer the 
anterior, and no sign of a perforation. The shape was more like 
that of Montacuta, and the lines of growth were regular and dis- 
tinct. On the right valve at its lower margin was seen a slight 
notch, and the few last incremental lines indicated that the notch 
was made in the last stages of the nucleus. It can only be con- 
ceived that the animal before this was a rover, that it then com- 
menced to fix a byssus, the animal dropping to one side and the 
notch caused by the lowermost valve growing around it, the other 
valve showing no signs of this notch. So soon however as the shell 
rested upon one side a different growth took place, a loose-tex- 
tured, colorless deposit rapidly formed, the outline becoming grad- 
ually circular and the lowermost or right valve growing rapidly 
