244 ' DISCOVERY REPORTS 



Mouth-parts : The mouth-parts of the Discovery material agree well with those of 

 Hoek's type-material, in which, in spite of their bad state of preservation, it was possible 

 to see them. Palpus conical, rather pointed, with spines at one side and at the point. 

 Mandible with four teeth and a pectinated inner angle. Maxilla I with a broad and 

 distinct notch without bristles; above the notch are stronger spines. Maxilla II broad, 

 with no notch on the middle of the front edge. A posterior lobe with bristles is differen- 

 tiated. Behind this is a small maxillary lobe. 



Number of segments of the cirri of the dissected specimen 



Cirrus I II III IV V VI CaudA 



, . ,^_»^ . . . ^.^j^^ appendage 



Segments 7 9 13 14 14 15 17 17 16 17 17 17 i 



Cirrus I with rami unequal in length. The other cirri with rami sub-equal in length. 

 The segments of the sixth cirrus with four pairs of spines on the front edge. 



Caudal appendage short, with only one segment; one large bristle at the top. The 

 appendage about half the length of the proximal segment of the pedicel of the sixth cirrus. 



ComplemeJitol male (Fig. 8,/) of the sack-like type, without any traces of valves, 

 smaller than in S. botellinae. The surface is minutely spinose, as in other males. 



Scalpellum convexum, Nilsson-Cantell, 1921. 



Nilsson-Cantell, 1921, Zool. Bidrag Uppsala, vii, p. 194. 



St. 27. 15. iii. 26. West Cumberland Bay, South Georgia, iiom., r. m. Gear DL. Two full- 

 grown specimens on Hydroids. 



St. 140. 23.xii. 26. Stromness Harbour to Larsen Point, South Georgia. 122-136 m.,gn.m. st. 

 Gear OTL. Many specimens of different ages on Gorgonians. 



St. 156. 20. i. 27. 53° 51' 00" S, 36° 21' 30" W. 200-236 m., r. Gear DLH. Some smaller 

 specimens on Gorgonians. 



Distribution. South Georgia. The Discovery localities agree well with the localities 

 of the type collected by the Swedish South Polar Expedition, 190 1-3, also from South 

 Georgia, in 1 10-3 10 m. 



Discussion and Supplementary Description. This species, first described by me 

 in 1921, is now found again in Antarctic regions. There are some species from the same 

 parts of the ocean nearly related to this, namely S. bouvieri, Gruvel, 1906, and S. 

 weltneri, Gruvel, 1907. I first thought that all three were the same species, but since 

 I have compared the types with the present material I must affirm that they are all 

 distinct species, though the differences are not very great. S. bouvieri was identified by 

 Nilsson-Cantell (1926). As the figures of both species, S. weltneri and S. bouvieri, do not 

 give an exact impression of the shape of the plates, I must here note that the species are 

 very closely related in external characters. Both have the carina concave dorsally, more in 

 the latter species than in the former. S. convexum differs from both distinctly in the 

 strong dorsal convexity of the carina. Other differences in the plates also exist. S. welt- 



