but the cluster is much more slender in proportion to their 
length and the arrangement of the capsules is less regular. 
"The species is known only from Greenland and the Polar Sea." 
That the egg-clusters obtained by Mr. Fuller were those 
of C. decemcostatus was readily proven by finding among some 
egg-capsules of B. undatum in the collection of the Society a 
small cluster of the former, about one inch in height, from which 
I took embryonic shells of C. decemcostatus about 7 mm. in 
length; the smooth protoconch of about two whorls was followed 
by half a whorl, having about nine revolving ridges, the anterior 
ones poorly defined. 
The three cylindrical clusters of egg-capsules were obtained 
from a depth of about 45 fathoms between the Georges and 
Nantucket Shoals, attached to living specimens of the Great 
or Deep-water Scallop (Pecten magellanicus Gmelin). Two 
were attached to one shell about 1.25 inches apart, as shown 
in the photograph (Plate 1, fig. 2). The length of the clusters 
varies from 3 to 3.5 inches (75 to 90 mm.) with a diameter at 
the base of about 1.5 inches (37 mm.) and at the top 1.25 inches 
(31 mm.). For a better anchorage the attached portion of the 
base extends on all sides about a quarter of an inch beyond 
the capsules. There are between 45 and 50 capsules in each 
cluster, which, when taken from the water, were lemon yellow 
in color. Each capsule is about half an inch in diameter, convex 
above and roughened by reticulated lines. As the specimen 
dries, these lines become more pronounced by the contraction 
of the interstices, giving the surface a pitted appearance. The 
attached portion of each capsule is broad, contracted above and 
then expanded into the broad capsule, which is folded down 
on the one below; the base of the upper one is usually attached 
to the upper sides of the two below, thus overlapping like the 
tiles on a roof and arranged somewhat spirally, the contracted 
portion serving as a hinge, beneath which are openings through 
which water can flow and the young escape. As the opening 
of the capsule is a wide slit at the end just under the top, this 
portion of the capsule is always free. 
There were apparently from three to f<jur oggs in the fresh 
capsules, but in the old dry cai^sules there w(M-e only one or 
two young shells. !ii tliis coiuK'ction it might be of inti^rest 
again to refer to tiic following; paragraph in Dr. Da'i's paper. 
'Tn many cases, as in Buccinuni and Btisycon, it was shown 
many years ago by Lov^n and others that a single ovicapsiile 
