80 AUSTRALASIAN ANTARCTIC EXPEDITION. 



others they are present on the 1 2th on one side, and on the 1 1th on the other. Six of 

 them have quite small gills on the llth segment on both sides. One has a gill on llth 

 on one side, and on the 13th segment on the other. 



Some of the above worms are sexually mature. But in some that are quite 

 young, measuring only 5 mm.. I find likewise that in some individuals the gills com- 

 mence on the 12th on both sides, in others on the llth, in others again on llth and 12th. 

 In one specimen of still smaller dimensions there is a very small gill on the 10th 

 segment. 



We may, therefore, I think, regard the position of the first gill as being on the 

 12th segment as a specific character. 



The anus is surrounded by a thickened smooth ring, slightly notched dorsally 

 and ventrally; I see no distinct anal cirri in any of the many specimens examined. 



Localities. -- 



Boat Harbour, Commonwealth Bay (collected by Dr. A. L. McLean), 2-4J 

 fathoms. 



Distribution. Near Port Lockroy (Gravier). 



Remarks. This worm agrees well with that described by Gravier under the name 

 of 8. kergudensis Mclntosh. At the same time he points out several features 

 in which his worms differ from ^he account given by Mclntosh, and he states 

 " that it is with doubt that I identify with that species the seven small 

 Ariciens obtained from the Roosen Channel, Port Lockroy." The shape of 

 the dorsal and ventral " cirri" (or lips, as I prefer to term them) differs, 

 as also does the shape of the gills, which Mclntosh figures as filiform. Tt may 

 be noted that Mclntosh's account and figures are not in absolute agreement 

 as to the position of the gills. Gravier, following Ehlers, suggests that S. 

 kergudensis may be the young of S. armiger. His specimens, which were 

 but seven in number, were of small size, about 17 mm., and badly preserved, 

 whereas mine are quite well preserved, and many are sexually mature. And 

 since the gills commence almost constantly on the 12th segment, whereas 

 those in 8. armiger begin on the 15th-18th, and rarely as far forward as the 

 10th, it is evident that this surmise is incorrect, at any rate for the species 

 studied by me, and, as I have stated, these agree quite well with those 

 described by Gravier. 



Recently, Fauvel (1916) has given a more detailed account of S. ker- 

 gudensis, and finds some differences from that of the previous authors. But 

 it is clearly different from the present worm, in that the gills appear on the 

 18th- 20th segment; he finds also certain peculiar cheetse -forked, pectinate 

 bristles commencing on the 10th or 9th segment; these, as I have men- 

 tioned, are not present, while on the 10th or llth segment are one or two 

 acicula, which are likewise absent from these worms. 



