HYDE: CAMAROPHORELLA. 43 
junction, one is slightly broken but not in the place where it would 
be expected if it had been torn from the crus; the three others show 
the ends of the lamellae, one with both lamellae, without a fracture. 
In the specimen in which the lamella and crus are seen in conjunction 
(the same one from which fig. 13, pi. 7, is reconstructed) the posterior 
margin of the lamellae rests alongside the outer edge of the blade of 
the crus but does not touch it. 
The ribbons of the brachidium are preserved as flattened hollow 
tubes and any fracture made recently would be easily detectible. If, 
however, the fracture was made before mineralization took place, it 
might be difficult or impossible to detect a break especially if it were 
small. In some specimens, however, they have been recognized with 
ease. It must be noted further that in several cases where the spirals 
or juga are preserved, they are not in the exact position which they 
originally occupied. Even in the specimen just described (pi. 7, 
fig. 13) there is a slight displacement. The structures are held in the 
position in which they are now found by infiltered sediment or mineral 
matter and any displacement must have occurred before this infil- 
tration took place. If the lamella and crus were only slightly attached, 
the fracture resulting upon displacement might have been entirely 
covered over and concealed. 
In the specimen referred to above in which lamella and crus are in 
close apposition, the brachidium was preserved without a fracture in 
the entire delicate structure, but there is a slight shifting of the whole 
from its original position and the point of yielding has been the sup- 
posed point of attachment. This specimen is so delicate that it has 
been badly broken since it was collected, but the relation of the end of 
the primary lamella to the crus is clearly shown; the two are not in 
contact but separate by possibly one tenth of a millimeter. Further, 
both lamella and crus are firmly imbedded in the matrix partially 
filling the shell cavity, so that the movement must have taken place 
immediately after death, probably as a result of the weight of the 
brachidium and of the decaying organic matter. Whatever the 
cause, it was not sufficient to produce any other disturbance. This 
example, together with the four others in which the primary lamellae 
are preserved unbroken to the end, although separated from the crura, 
and the three specimens in which the crura are unbroken with no 
remnant of the lamellae still adhering to them, are considered strong 
evidence in support of the view that there was only a very slight attach- 
ment or very incomplete spiculization at the point of attachment. 
