IÖI 



is strongly sinuous by the terminations of the keels, of which the upper one becomes doublé 

 at a little distance from the mouth, columellar margin connected to the outer one, by a thin 

 layer of enamel on the body-whorl, it is first strongly excavated above by a rather deep sinus, 

 reaching the columellar tooth, below this tooth it is again concave and terminates in an angle 

 when it joins the basal margin at the point terminating the umbilical keel. 



Alt. 3, lat. 3 1 /., ; apert. alt. i 5 /,., lat. i 3 / 5 , diam. of umbilicus about i Mill. 



These measurements will be more or less altered in a specimen with complete aperture. 



This new species has some resemblance with S. elegans Jeffr. but differs sufficiently by 

 the number of keels and by the aperture, which, though broken, has other characters, the 

 columella in elegans being much longer than it can be in a complete specimen of 5. Sykesi, 

 the whole shape of S. elegans is consequently more obliquely elongate, the sculpture is much less 

 developed in the new species. It has also resemblance with 5. polita Verco (Trans, and Proc. 

 Roy. Soc. South Austr. Vol. 30, 1906, p. 222, PI. 9, fig. 3, 4, 5), especially in its sculpture, 

 but that species, according to Verco (1. c. PI. 9, fig. 5) is only rimate and the keels are blunt 

 and placed in a different manner. The nearest ally is .S'. tonica Wats. (Journ. Linn. Soc. Lond. 

 187S, Vol. 14, p. 589; " Challenger"-Gastrop. p. 107, PI. 7, fig. 3), and indeed I have been in 

 doubt if it should not be an oriental variety, but that species, as figured, is much more depressed, 

 has a more conspicuous liration at some distance from the suture, and the radiating sculpture 

 seems to be more conspicuous in 5. ionica. 



Named in honour of Mr. E. R. Sykes, who has sent me for comparison a beautiful lot 

 of specimens of this genus. 



4. Segnenzia costnlifcra n. sp. PI. XII, fig. 7. 



Stat. 211. 5°4o'.7 S., i2o°45'.5 E. I! 5§ M. Coarse grey sand. 1 Spec. 



Shell rather small, conoidal, with a high spire and convex base, scalar, rimate, yellowish- 

 white. Whorls about 7, of which the upper one forms the smooth, bulbous nucleus, foliowed 

 by 2 whorls, which have a strong median keel and traces of a third one below the suture; 

 these lirations become more conspicuous on the lower whorls, which have the median keel, 

 another one just below the suture and in some parts traces of a third one, running entirely 

 or partly in the deep suture; moreover the whole shell is covered with microscopic, close-set, 

 spiral threads; this sculpture is crossed by conspicuous riblets, fainter on the upper whorls, very 

 strong on the lower ones, and by very fine growth-striae ; the riblets are not close-set and form 

 conspicuous spines below the suture of the lower whorls; when they cross the upper spiral, they 

 run obliquely from behind and are curved in the lower part of the space between the upper 

 and median keel, being concave below; below this median keel they are convex; on the last 

 whorl runs a third keel, which is crenulated by the ribs, this is also the case with the median 

 keel, though not so strong; at some distance from the third keel a fourth one makes its 

 appearance, this is a little fainter and less crenulate, the riblets between it and the third keel 

 being also weaker. The interspaces of the keels described above are conspicuously concave. 

 From the fourth keel untill the centre run 5 spirals, of which the distal one at a considerable 



73 



SI ROG A-EXPEDITIE XLIX' II. 24 



