Gatty Marine Laboratory, St. Andrews. Ill 



4. On Sigalion squamatum, Belle Chiaje, and its Relation- 

 ships with S. Mathildas, And. & Ed., and S. Buskii, 

 M'Intosh. 



In his recent valuable papers on the Annelids of the shores 

 of France S. squamatum of Delle Chiaje * has been confused 

 by Baron de Saint-Joseph with S. Mathildas, Audouin and 

 Milne-Edwards. Thus in the u Anne'lides Polychetes des 

 Cotes de Dinard " f, under the title of Sigalion squamatum, 

 D. Ch., De Saint-Joseph gives descriptions and figures appli- 

 cable to S. Mathildas, Aud. & Ed. A glance at figure 27, 

 pi. xii., of this paper would alone be conclusive, since the 

 papilla on the dorsal edge of the ventral division of the foot 

 is characteristic of S. Mathildas and is absent in S. squamatum. 

 He also points out the agreement of the pinnate papillae of 

 the edges of the scales with those figured by Claparede, and 

 this is fortunate, as his own figure J of these is diagrammatic, 

 though he correctly observes that the pinna} are about twenty 

 in number (PI. II. fig. 14) on each side, a feature wholly at 

 variance with the condition in S. squamatum, D. Ch., which 

 has about eight pinna} of quite a different shape on each side 

 (PI. II. fig. 13). The characteristic curve of the main nerve- 

 branch and the arrangement of its twigs to the pinnate 

 papilla}, as shown by Claparede, meets with De Saint-Joseph's 

 approval. It is interesting that in this respect S. Mathilda} 

 differs from- S. squamatum. He gives but two " coussinets 

 vibratiles " (ctenidia), whereas three occur both in this 

 species and in S. squamatum. The short papilla on the 

 upper border of the ventral division of the foot is diagnostic 

 of S. Mathildas. The bristles of the two species are as 

 characteristic as are the pinnate processes of the scales, for the 

 stouter bifid forms of the ventral division of the foot with 

 but a single bifid terminal appendage are absent in S. Ma- 

 thildas. In his more recent paper on the " Anne'lides Poly- 

 chetes des Cotes de France " § he inserts S. Mathildce, Aud. 

 & Ed., as a synonym of Sigalion squamatum, Delle Chiaje, 

 and makes certain " additions and modifications " to his 

 former account. Amongst these is the remarkable statement 

 and accompanying figure to the effect that the dorsal bristles 

 are bifid at the tip under a power of 465 diam. These finely 

 tapered serrated bristles end in a simple hair-like point as iu 



* Descriz. e not. v. pp. 58 and 107, tav. xxvi. figs. 3, 11, aud 12. 



t Ann. d. Sc. nat. 7 e , ser. xx. p. 203 (1895). 



X PI. xi. tig. 21. 



§ Ann. d. sc. nat, 8", s6r. v. p. 230 (1897). 



9* 



