47 58 Proceedings of the Royal Irish Academy. 



the head. They are smooth and subulate, without papillae, but with 

 numerous palpocils. The massive base on which they rest bears a few 

 cylindrical papillae. On the ventral side of the head, beneath the median 

 tentacle, is a large facial tubercle (figs. 14 A, B, /, fig. 14 c), seated on a 

 rounded base. 



The whole of the ventral surface of the body and parapodia is covered 

 with small globular thick-walled papillae, those in the mid-ventral line being 

 the smallest. The lower lip of the mouth is thickly set with cylindrical 

 papillae. The anal segment is button-shaped, and carries two long slender 

 anal cirri. 



There are 56 pairs of elytra, placed in the normal manner on segments 

 2, 4, 5, 7, 9, 11 . . . 23, 24, 25, etc. The elytra cover most of the dorsum, 

 leaving only a narrow median space in the anterior region. In the Blacksod 

 specimens there is a large amount of opaque white pigment on the elytra, 

 especially round the outer margin, but in the Portstewart specimens this 

 pigment is absent, and the scales are translucent, with well-marked hilum 

 and indistinct areolation. 



The first pair of elytra (fig. 14 d) are rounded, smaller than the rest, 

 with a few papillae on the upper surface near the edge, and about 32 on 

 the border. The papillae are short, cylindrical, often with swollen tips. 



On the succeeding segments the elytra (fig. 14 e) are larger, irregularly 

 oval in shape, without papillae on the upper surface, and with about 18-25 

 papillae on the margin. The papillae are moniliform, with swollen tips, and 

 with a granular core. 



The scales on the posterior segments are of a more transversely elongate 

 oval shape, with fewer papillae. 



The first foot resembles the others except for the fact that the ventral 

 cirrus is much larger and is fixed nearer to the median line (fig. 14 b). 

 It rises from a conspicuously swollen base, which is thickly covered with 

 papillae except on the inner side. 



The 15th foot (fig. 14 f) is distinctly bifid, with a large spine in each 

 branch. The dorsal lobe forms a flattened hood-like expansion over the 

 ventral lobe, and is continued laterally along the sides of the ventral lobe 

 towards the ventral cirrus. In this lateral region it bears a series of 6 long 

 cylindrical papillae. Fig. 14 G shows the dorsal lobe as it appears when 

 viewed from above. The setae are of two kinds. On each side there is a 

 bunch of long slender serrate setae (fig. 14 L, b) which emerge on the ventral 

 side of the dorsal lobe. Along the margin there is a series of short bent 

 setae (fig. 14 l, a) which taper abruptly to a fine point, and have a number 

 of teeth near the bend. These setae emerge on the dorsal side of the dorsal 



