A. E. Yew ill — Earth American Cephalopods. 
215 
and tlie horny ring has a corresponding notch ; the outer or hack 
portion is much swollen and produced downward and backward, 
and here the horny ring is correspondingly broad. The aperture 
is nearly circular, but is rather shorter from front to back than 
transversely. In this and some of the other suckers of similar 
size, the entire circumference of the margin is furnished with rather 
large sharp denticles which are strongly inclined inward and con- 
siderably larger on the outer than on the inner margin. There 
are about thirteen of the large teeth, occupying rather more than 
half the circumference; these are broad at base, bevelled off to 
an acute edge on the sides, and somewhat acuminate, with sharp 
tips. Those on the middle of the outer border point inward to 
the center of the sucker, but those along the sides point rather 
obliquely to the front margin. The front margin is occupied by 
about seventeen smaller, unequal, acute, denticles, those in its cen- 
ter the smallest and most regular ; these are acute-triangular and 
their points are directed more upward than those of the opposite 
edge. The horny rings are light yellow (when dried they are white 
and osseus), their denticles yellowish white, and often silvery white 
and lustrous at tip and along their edges, especially when dried. 
The suckers smaller than the above have fewer of the larger outer 
teeth, and usually fewer and less perfectly formed teeth along the 
front margin. Those that have the aperture 7 mm or less in diameter 
usually have the front margin of the ring only irregularly fissured, 
with the intervals minutely denticulate or crenulate, while the outer 
half of the margin may bear nine or ten large and well-developed 
denticles, with broad stout bases and sharp edges and tip ; the edges 
of these teeth along the middle ai*e usually convex, and then the 
outline is incurved to the aerate point. One of the smaller suckers 
examined has the aperture about 4-5 ram in diameter, with the same 
form as the larger ones; this has about six large, sharp, denticles, like 
those above described, on the outer half of the margin of the rings, 
while the front margin is nearly entire and smooth. The smallest one 
(j) is similar, with but four distinct, large denticles, with another 
imperfect, lobe-like one, on one side, and with a smooth front margin. 
The three largest suckers, (Plate XVII, fig. 9), supposed to be 
from near the base of the ventral arms, have about 45 marginal 
denticles, of nearly uniform size, and less incurved than in those 
above described. In these the back side of the horny ring is less 
expanded, and therefore the suckers were less oblique than in the 
smaller ones. The largest of these («) had the aperture 20 mm in 
diameter. 
