8CISSUEELLA. 55 



arcuately plicate above the carina, below it with striae of growth ; 

 aperture large, irregularly circular, very slightly expanded at the 

 basal margin, peristome continuous, slit narrow, profound. 

 Alt. 1, diam. 1J mill. (Smith.) 



Swain's Bay, Kerguelen Id. 



S. supraplicata E. A. Smith, Ann. Mag. N. H. xvi, p. 72, 1875 ; 

 Philosoph. Trans. Roy. Soc. Lond., vol. 168, p. 176, t. 9, f. 5, 1879. 



S. alta Watson. PI. 58, figs. 4, 5. 



Shell globose, thin, transparent, strongly sculptured, with a tumid 

 base, a small umbilical chink, a short subscalar spire (on which the 

 old canal slit forms the edge of the successive whorls), and a small- 

 ish somewhat prominent rounded tip. Sculpture : Longitudinals fre- 

 quent, strongish, rounded, curved riblets radiate out from the sutures ; 

 they are of much the same strength on the base as above. Spirals — 

 at about one-third of its height from the suture, the last whorl is 

 carinated somewhat feebly by the old canal scar, which is depressed 

 and finely scored across between the narrow slightly projecting lip- 

 edges ; on the upper surface a few very obsolete spirals may be seen ; 

 the whole base is reticulated by spiral threads, which are closer set, 

 but almost as strong as the radiating riblets. Color white. Spire 

 rather depressed, conical, rising regularly to the extreme tip. Apex 

 round and prominent. Whorls 5, flat and sloping above, carinated ; 

 below the carina towards the mouth slightly openly constricted and 

 then tumid on the base. Suture impressed. Mouth round. Outer 

 lip freely curved. Inner lip thin, concave at the base of the pillar, 

 straight, rounded, and very much expanded on the pillar, with an 

 angulated and very patulous junction to the outer lip in front ; there 

 is a small umbilical furrow and chink half hidden behind it. 

 (Watson.) Alt. -082 in., diam. -08. 



This species extremely resembles Scissurella eximia, Seg. (see Form. 

 Terz., p. 272, pi. 16, fig. 32), both in form and sculpture, but the base 

 is more tumid, the whole shell more compressed, and the aj^ex is a 

 little larger and more exserted. In its strong, radiating ribs it is like 

 Scissurella staminea A. Ad., from Japan, but it is much larger and 

 higher. ( Watson.) 



Off Culebra Island, West Indies, in 390 fms. ; off Fay al, Azores, in 

 450 fins. 



Scissurella alta Watson, Challenger Rep., Gasterop., p. 113, t. 8, 

 f. 1, 1886. 



