112 Prof. M'lutosh's Notes from the 



allied forms. The author has apparently been deceived by a 

 broken example, for such a condition as he figures is at 

 variance with the morphology of the group as well as expe- 

 rience, though occasionally the shorter forms at the internal 

 edge of the tuft show such a condition from injury. He 

 rightly describes the superior group of the ventral bristles 

 with the tapering tips and whorled spines, though his figures 

 of this and the other forms are indefinite. While he gives a 

 correct account of the forms with a single terminal (bifid) 

 appendage which commence the inferior group of ventral 

 bristles, he omits to show the essential differences in the 

 structure of the bristles immediately above the spine of the 

 ventral division of the foot in the two species. In S. squa- 

 matum, D. Ch., the process for the spine projects more 

 prominently, and above it, besides the stronger forms with 

 the ends of the shafts closely serrated, there are several stout 

 bristles with a single terminal (bifid) appendage. Ln 

 S. Mathildce, besides the presence of the dorsal papillge on the 

 inferior division of the foot, the tip differs in outline, being 

 obliquely truncate. Moreover all the bristles above the spine 

 have slender, articulated, tapering tips, minutely bifid. Both 

 species have four eyes, so that no weight is to be placed on 

 their absence in indifferent preparations. 



It is not remarkable that the acute and accomplished 

 Clapar^de *, who worked at Naples, should have been puzzled 

 by the form actually meant by Delle Chiaje, for in the 

 descriptions of the latter author there is nothing definite, and 

 certainly his peculiar figure of the pinnate processes of the 

 scales might pass for either species, so tliat the blame does 

 not really rest with the author first mentioned. It is the 

 inaccurate figure in most cases which has been so disastrous 

 in the history of the Annelids, and the failure to give in a 

 few words the vital points of distinction. 8. squamatinn is a 

 larger species than S. Mathildce^ which Clapar^de appears to 

 have had before him when making his descriptions and 

 figures. The curve of the great nerve-cord to the outer edge 

 of the scale, its size, and the thickness and brevity of the 

 large branches to the pinnate papilla, without reference to 

 the other points, make it clear that it was not S. squamatum^ 

 D. Ch., but 8. Mathildce, Aud. & Ed., that the Swiss author 

 described. 



While therefore there can be no dubiety between 8. squa- 

 matum, Delle Chiaje, and 8. Mathildce^ Aud. & Ed., there 



* Anuel. Chet. Nap. p, 100, pi. iii. fig. 3, and ibid. Suppl. p, 20, pi. ii. 

 fig. 3. 



