POLYCH^TA. — ^BENHAM. 201 



The genus was formed by M'Intosh for a single specimen, 

 S. ceramensis} and Moore has found it off the coast 

 of Japan, his species, 8. jormosus,^ is, like mine and the 

 type species, very imperfect, and we know nothing of the 

 elytra in the genus. But the chaetae are so characteristic 

 that there is no mistaking it. 



Loc. — Southern coast of Australia. 



Family SIGALIONID.E. 



Genus Thalanessa, Baird. 



Thalanessa oculata, M'Intosh. 



(Plate xlv., figs. 118-123.) 



Thalanessa oculata, M'Intosh, Chall. Rep., Zool., xii., 1885, 

 p. 142. Id., Treadwell, Bull. U.S. Fish. Comm., xxiii., 

 3, 1906, p. 1157. 



A single individual was obtained which is smaller than the 

 type. It measures 30 jnm. in length by 1 mm. across the 

 body, and 3 mm. over the parapodia. It is a good deal 

 shrunken, as if it had been placed in very strong spirit. 

 There are 61 segments, but it is apparently imperfect. 



The account in the " Challenger " is so full that I need 

 not add any further data, but I have given figures in addition 

 to those already published, namely of a typical foot (PI. xlv., 

 figs. 119, 120), and of the peculiar anterior feet, in which the 

 membranous expansion of the neuropod and digitate noto- 

 podial processes are so well developed. The parapodia are 

 remarkably long ; their appearance will be gathered from the 

 figures herewith (PI. xlv., figs. 121-123). 



MTntosli's figure of the elytron is not quite typical ; it 

 represents an anterior one, while those in the greater part of 

 the body are not exactly " reniform," as he describes them. 

 Each has a deep excavation on the anterior maigin, but the 

 outer or ventral boundary is much longer than the upper, and 

 the scale covers almost four segments as shown (PI. xlv., 

 fig. 118). It is attached to the elytrophore near its anterior 

 dorsal margin. 



I find that the body-wall is splashed with pale nut-brown 

 markings on each side of the anterior segments, which are 

 visible through the transparent elytra, which themselves 



1. M'Intosh— Chall. Rep., Zool., xii., 1885, p. 103. 



2. Moore— Proc. Acad. Nat. Sci. Philadelphia, 190.3, p. 403. 



