210 BUNODID^E. 



sometimes having a tendency to run in longitudinal lines, but more 

 generally irregularly scattered, leaving intervals of three or four times 

 their diameter in ordinary states of distension, and these intervals have 

 often a silky lustre. Substance firm and even cartilaginous. Margin 

 entire, but roughened with the scattered warts, forming a thick parapet, 

 separated from the tentacles by a broad fosse. In freedom, the column is 

 generally more or less disguised by fragments of stone and shell adhering 

 to the suckers. 



Disk. Flat, circular in outline, plane but overarching. Radii con- 

 spicuous chiefly by colour. 



Tentacles. Arranged in five rows, the first set at about half radius, — 

 5, 5, 10, 20, 40 = 80; the first and second so nearly equidistant from the 

 centre as to seem but one. Their form is conical, thick at the foot, 

 regularly tapering to a point, which is sometimes slightly inflated. The 

 animals appear to have the power of changing the shape of these organs at 

 will ; for I have had individuals, in which the tentacles, after having for 

 a while borne the ordinary conical form, suddenly became nearly cylin- 

 drical, with truncate extremities, and maintained this form for a long time. 

 These organs are nearly equal among themselves, and their length is about 

 equal to one-third of the diameter of the disk. They are capable of little 

 flexure, and are generally spread in a regular star-like manner, the outer 

 rows deflected , the inner erect, and the intermediate ones horizontal. They 

 are powerfully adhesive. 



Mouth. Frequently elevated on an eminence of varying form and 

 dimensions. Throat and stomach often protruded to such an extent as to 

 conceal the whole disk. Gonidial tubercles two pairs, small. 



Colour. 



Column. Dull green, streaked and flaked with crimson, with pale grey 

 warts. 



Disk. Glaucous-olive, with conspicuous radial bands proceeding from 

 each outer tentacle, in pairs, which ciu-ve around the foot of each tentacle 

 of the higher rows, an 1 are lost at varying distances from the centre ; 

 those pairs which enclose the inner tentacles extend farthest and are most 

 conspicuous. The colour of these bands is scarlet, often edged with white, 

 and they are highly characteristic of the species. 



Tentacles. Pellucid light brown, with a band of opaque white across the 

 foot, which frequently stretches a little way up each side: a broad band 

 of crimson surrounds the middle, bounded below, and sometimes above, by 

 a narrower band of sub-opaque white. All these bauds are undefined, and 

 are often rendered sub-pellucid by distension. 



Mouth. Generally tinged with crimson. Gonidial tubercles crimson. 

 Throat and stomach light grey. 



