1873.] 3865 | Morse. 
spicuous, and the shelly matter is white. The left valve adds con- 
centric layers around its entire margin, not excepting the hinge 
margin. The lower valve appears to grow from its posterior and low- 
er half, the successive accretions being produced around the bys- 
sus. This growth for a while seems to take place exclusively from 
the posterior half of the shell, limited in front by the byssus, and even 
after this growth has increased to twice the diameter of the embryo 
‘shell, only a slight increase is noticed on its anterior margin, this lat- 
ter addition being slightly reflected. The left or upper valve grows 
more rapidly, so that its margin overlaps the right valve at all points. 
As the animal increases in size, the foramen increases also, and its 
earlier boundaries are consequently absorbed. 
“Tt will be seen by reference to the figures, that the growth of the 
perforated valve is first posterior and downward, from the posterior 
half of the shell; it then grows forward, avoiding the byssal plug, and 
by successive additions surrounds the byssal plug, and ultimately 
reaches the umbones of the larval shell, and even beyond and behind 
this region. 
“ From these facts it is obvious that at an early stage the animal is 
free, and for a time locomotive; that it has an elongate, oval, bivalve 
shell, with close and regular lines of accretion, and that during the 
latter stage of this growth it becomes attached by a byssus passing 
from between the valves of the shell, as in Mytilus; that before the 
growth of the larval shell is completed it drops over to one side, since 
one valve only shows the notch upon its margin, and that so soon as 
this growth ceases, a new growth takes place, looser in texture, and 
white in color, as above described.” 
The figures are here given which accompanied the paper from 
which this extract is taken. At another time I hope to meet with 
living examples of Anomia in this early stage. The specimens from 
which the above studies were made, I found upon dried sea weed, but 
the shells told the story plainly enough, as will be seen by the figures. 
Let us again revert to Steenstrup’s views regarding the affinities of 
the Brachiopods. In the Proceedings of the Royal Danish Academy 
for the year 1848, pp. 88, 89, Prof. Steenstrup again refers to the 
supposed deviations of Anomia from the Lamellibranch, and showed 
that they were not only closely related to the other Monomyarians, 
but had no sort of approximation to Terebratula, or the other Brach- 
iopods. In that meeting he indicated what he considered the true 
place to which the Brachiopods should be assigned. 
