[45] CErilALOPODS OF NORTHEASTERN COAST OF AMERICA. 255 



arms and the distal half of the other arms. The diameters vary from 

 gmm to 24">™ externally ; the apertures from 3.5 mm to 20 mra . 



One of the most perfect of these suckers (b) is preserved in alcohol, 

 with the soft parts (Plate IX, figs. 5, 0), and was sent to me from New- 

 foundland by Mr. Harvey. This has the greatest external diameter 

 22 mm ; diameter of aperture, 10 mm ; height of cup (outside), 16 mm ; height 

 at center, 15 mm ; height near inner margin, at attachment of pedicel, G ,rm ; 

 length of pedicel, 14"'""; diameter of pedicel, 1.5 mm . In a side-view the 

 sucker is oblique and gibbous ; the lower surface is convex centrally, but 

 has a deep notch or pit near the front margin, in the bottom of which 

 the slender but strong pedicel is attached, and the horny ring has a 

 corresponding notch 5 the outer or back portion is much swollen and 

 produced downward and backward, and here the horny ring is corre- 

 spondingly high. 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 fur- 

 nished with rather large, sharp denticles, which are strongly inclined 

 inward and considerably 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, beveled 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 center 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 osseous), their denticles yellowish white, and 

 often silvery white and lustrous at tip and along their edges, especially 

 when dried. The large suckers of this form I refer to the basal half of 

 the lateral and dorsal arms. 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""" 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 tips ; 

 the edges of these teeth along the middle are usually convex, and then 

 the outline is incurved to the acute 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 simi- 

 lar, with but four distinct large denticles, with another imperfect, lobe- 

 like one on one side, and with a smooth front margin. These probably 

 came from the distal half of the various arms. 



