27 



trill in form, with the outer angle round, the sides slightly con- 

 convex and generally smooth, except toward the end, where it 

 begins to enlarge. Although so slender, these arms are very 

 strong and elastic. The terminal portion, hearing the suckers, is 

 30 inches in length and expands gradually to the middle, where it 

 is 4-5 to 5 inches in circumference (6 inches when fresh), and 1-5 

 to 1-6 across the inner face. The sucker-bearing portion may be 



in which the arm is triquetral, with margined lateral angles, and 

 gradually increases up to the maximum size, the inner face being 

 convex and bearing about forty irregularly scattered, small, flat- 

 tened, saucer-shaped suckers, attached by very short pedicels, and 

 so placed in depressions as to rise but little above the general sur- 

 face. These suckers have narrow marginal rings, with the thin 

 edges nearly smooth, or minutely denticulate, and -10 to -V2 of an 



membrane. These suckers are at first distantly scattered, but be- 



five or six very irregular rows, covering the whole width of the 

 inner face, which becomes her* 1-6 inches broad. Scattered among 

 Ihese suckers are about as many low, broad, conical, smooth, cal- 



the apertures of the adjacent suckers. These, without doubt, are 

 intended to furnish secure points of adhesion for the correspond- 

 ing Mirkers of the opposite arm, so that, as in some other genera, 

 these two arms can be fastened together at this wrist-like portion, 

 and thus they can be used unitedly. By this means they must be- 

 come far more efficient organs for capturing their prey than if used 

 separately. Between these smooth suckers and the rows of large 

 ones there is a cluster of about a dozen small suckers, with ser- 



The second division of the sucker-bearing part of the arm suc- 

 ceeds the small suckers. Here the arm is well rounded on the 



eac jj Jj,],., alternating with the large ones. The inner edge is bor- 



