294 EITXOA NODOSA. 



E. oerstedi, again, the anterior edge of the typical scale (anterior third) is smooth, but 

 otherwise the entire margin has short clavate cilia scattered at intervals amongst the 

 tubercles and spines, the outer edge having these no more prominent than the inner. 



Considerable variation exists in regard to the size and distribution of the smaller 

 spines over the surface. Thus in the figure from the specimen in the British Museum these 

 are comparatively small both towards the inner border and along the anterior edge, but, 

 on the general surface, the size increases while the number diminishes. The contrast 

 between the outer and the inner borders is marked, the former having fewer and larger 

 spines. The number of the large papillae along the posterior edge is nine to eleven, 

 which is more than usual, and some of them show spinous tips. The cilia are 

 confined to the outer edge. 1 An increase in the size of all the spines takes place in 

 an example from Spitzbergen, the larger forms on the general surface being proportionally 

 few. Only five large tubercles are present, with traces of spines at the tip of one or two ; 

 some sparsely distributed cilia occur along the posterior border as well as the denser 

 series of the outer edge. In fine specimens from the Gulf of St. Lawrence the propor- 

 tions of the various spines agree rather with the British forms, but a few short cilia are 

 found along the posterior border in addition to the longer outer series. 



Colour. — Wo fresh example has been seen, so that all that can be said is that the 

 scales are marked with reddish-brown or madder-brown touches, darkest in the anterior 

 scales. Malmgren observes that the scales have a violet-brown hue, generally with a 

 white spot in the middle. 



Feet. — The first foot — bearing the tentacular cirri — has a few (about three) bristles 

 which conform to the type of the dorsal, being stout, slightly curved, and spinous on the 

 convex margin, with a short, smooth tip, which affords a contrast to the more elongate 

 tip in E. oerstedi. 



The second foot is distinguished, as usual, by its long ventral cirrus, and by 

 the diminution and modification of its parts. The dorsal division has bristles of 

 the ordinary type. The tip of these is short and smooth, and the curvature of the inner 

 bristles is marked. The same foot in E. oerstedi has much longer and less curved bristles, 

 and the smooth region at the tip is longer and has a different outline. 



Ventrally is a group of much more slender bristles, with long spines on the distal 

 region and a needle-like, smooth extremity (Plate XXXVII, fig. 20). The tip of the 

 corresponding bristle in E. oerstedi is less elongate, and, instead of the finely-pointed tip, 

 it has the outline of a narrow knife-blade (Plate XXXVII, fig. 21). 



In the third foot the dorsal bristles are smaller than in the typical foot, but have the 

 same structure. The ventral bristles, again, though slender, already show shorter tips, 

 which, further, are less acute than in the first foot. 



The changes in the bristles have considerably advanced in the fourth and fifth feet, 

 so that the typical arrangement (Plate XLII, fig. 28), in which the longest dorsal 

 bristles reach a little beyond the spine of the ventral, is soon reached. These bristles 

 (Plate XXXVII, fig. 26) are shorter and more distinctly curved internally, the longer and 



1 A large Zetlandic example, the Antinoe zetlandica of Prof. Eay Lankester, corresponds in the 

 main with the foregoing, though the large spines posteriorly extend along the outer border, and, 

 like the former, the cilia are confined to the outer edge. 



