252 Messrs. Foord and Crick—-On Discites Hibernicus. 
exclusive of the inner area or umbilical slope. The inner area in 
the young is convex and imperfectly defined; in the adult it becomes 
flattened, slopes outwards from the umbilicus and is nearly equal to 
the periphery in width. 
The characters of the septa and suture-lines, as well as the length 
of the body-chamber, are not known, since the test is preserved over 
nearly the whole of the specimen. 
The entire surface of the free portion of the shell bears well- 
marked crenulated longitudinal lines; these become less marked as 
the shell increases in growth and finally disappear. On the inner 
area they disappear soon after the commencement of the second 
whorl; on the sides, at the end of the first half of the second whorl ; 
and on the periphery, some at the end of the second third of the 
second whorl and the rest at the end of the same whorl, #.e. at about 
one-fourth of the whorl from the aperture. 
The periphery at the end of the first fourth of the second whorl, 
1.e. at the commencement of the last whorl in the specimen, bears 
seven nearly equidistant, longitudinal, feebly crenulated lines, one 
median and three on either side, the outermost on either side being 
upon the subangular margin of the periphery. ‘The two lines, one 
on either side of the median line, disappear at about the end of the 
second whorl, and the rest at about the end of the second third 
of the same whorl (see D in Woodcut, p. 254). 
The lateral area at the commencement of the second whorl bears 
seven nearly equidistant longitudinal lines. Counting from the 
peripheral margin, the fourth, fifth and seventh lines are crenulated, 
the rest plain. The third is a very feebly-marked, plain line and 
soon disappears, leaving at the commencement of the last whorl 
the wide space between the second and third lines noted below. 
The seventh line is followed by a plain line which eventually 
becomes the umbilical margin. Inside this line three other lines 
are seen, the middle one of the three having just lost its crenulations. 
The third line appears to occupy the centre of the antiperipheral 
area, but this point cannot be satisfactorily determined since the 
whole of this area is not visible at this spot. 
At the end of the first fourth of the second whorl, 7.e., at the 
commencement of the last whorl in the specimen, the lateral area 
bears six longitudinal lines. The two outer lines are very fine and 
plain; the two next inner are distinctly crenulated ; these are suc- 
ceeded by a fine, uncrenulated, somewhat indistinct line, and then a 
crenulated line. Then follows the umbilical margin, which becomes 
more marked as the shell increases in size, and inside this margin is 
a single feebly crenulated line. The lines on the lateral area are 
equidistant with the exception of the second and third (counting 
from the peripheral margin), the space between these being twice 
as great as the space between any other two adjacent lines (see Cin 
Woodeut, p. 254). 
The surface of the test especially on the outer whorl is covered 
by very fine lines of growth, which, crossing the whorls somewhat 
obliquely backward, curve sigmoidally on the sides, and, becoming 
