Ginley.] 338 {March 1, 
From his article I will quote only those parts expressive of his investi- 
gations and views upon the crural processes or loop : 
“By carefully cutting and preparing favorable specimens, I have found 
that in place of the short crural processes so often figured, there is an entire 
and continuous loop connecting the spiral cones.”’ 
‘‘From its origin in the posterior portion of the first volutions of the 
spires, the loop curves gently forward and upward ; the central or elevated 
portion lying between and behind the cones, and forming a more or less 
abrupt curve or prolonged into a point directed toward the dorsal valve.”’ 
In paleontological studies, it is of rare occurrence that the student ob- 
tains a specimen of the Brachiopoda in which the internal appendages are 
not coated with silica, calcite, or some other mineral, and not unfrequently 
it happens that we notice two or more parts connected by a deposit of this 
kind. 
After having examined Professor Whitefield’s Plate, and also many 
specimens from the localities cited by him, I am inclined to believe that his 
examples were, to a slight extent, coated as above described. In October 
1877, I obtained, from the Devonian of Clarke County, Indiana, specimens 
of Alrypa* whose internal appendages were replaced by silica, and ap- 
peared to be free from the usual coating. 
It is hardly necessary to remark that these appendages are very fragile, 
and would hardly admit of the slightest touch, yet by careful cutting I was 
able to expose the posterior portion of the visceral cavity so as to permit of 
a close examination of the ‘‘loop connecting the spiral cones.’’ Several 
specimens were examined, each one of which shows the “‘ loop’’ to be com- 
posed of two long crural processes arising from the bifurcating of the pos- 
terior portion of the first volution of the cones. Following the convexity of 
the cones, they gently curve forward and upward, attaining a height of 
about one-third that of the cones. The extremities are separated by a space 
of about one sixty-fourth of an inch. 
The crural processes gradually twist until the lower surfaces present 
themselves successively to the anterior and top, abruptly expanding and 
curving posteriorly, the extremities pointing downward, the ends opposing 
each other with a rounded, semi-circular edge, the convexity being up- 
ward, the lower anterior edge being slightly developed beyond the upper 
edge so that, upon looking from above, the space between the edges ap- 
pears much wider in the middle. The specimens examined show the crural 
characters to be constant, and as above described. 
When we consider the slight space existing between the crural extremi- 
ties, and the frequency of their being coated, it is not to be wondered at 
that they should appear to be ‘‘ joined and continuous.”’ 
* A variety of A. reticularis L. 
