96 REV. E. BOOG WATSON ON THE 



Lacuna, Turton. 

 1. L.picta,n. sp. 2. L. (Hela) margaritifera, n. sp. 



1. Lacuna picta, n. sp. 



St. 122. Sept. 10, 1873. Lat. 9° 5' S. to 9° 10' S., long. 34° 

 49' W. to 34° 53' W. 350 fms. Mud. 



Shell. — Pointedly and squarely subglobose, small, thin, trans- 

 lucent, dull yellowish with crimson stains. Sculpture. The 

 lines of growth are few, faint, and irregular. Spirals. The 

 whole surface is covered with minute, close-set, scarcely raised, 

 rounded threads, about 0*002 in. apart. About ^ of the whorl's 

 breadth below the suture there is a slight angulation, and a still 

 fainter angulation surrounds the base. Colour yellowish, with 

 maroon stains markedly on two zones, one below the sutural an- 

 gulation, the other above that of the base, on both of which there 

 are arrow-headed, irregularly denned blotches, with small irregular 

 zigzags over the whole surface. Epidermis. There are traces of 

 an excessively thin horny epidermis. Spire rather high. Apex 

 small, rounded, and a little flattened and compressed, Whorls 5, 

 convex, flattened in the middle, which gives a certain squareness 

 of outline ; towards the upper part there is a slight angulation, 

 between which and the suture there is a slight constriction. The 

 mouth is f of the whole length. Suture distinct and slightly 

 impressed. 3Iouth very perpendicular, oval, bluntly pointed 

 above, and a little squarish from the straightness of the pillar and 

 of the outer lip. The outer lip is thin. The pillar is narrow, 

 bends a little to the left, is somewhat straight, but is a little 

 excavated, with a slight angulation at its junction with the body 

 and also in front. Inner lip crosses the body in a thin glaze ; 

 down the pillar it is flat, patulous and sharp-edged, behind it lies 

 the narrow shallow groove-like umbilicus, the exterior edge of 

 which, as in the genus generally, is continuous with the outer 

 lip, H, 0-15. B, 0-12, least O'l. Penultimate whorl 004. 

 Mouth, height 0*1, breadth 0075. 



This species a good deal resembles the young of L. crassior, 

 Mont., but is smaller, more globose, and much less angulated on 

 the base. It is very like the L. fragilis, Mke., but that species 

 is much more membranaceous, has the pillar more curved, and 

 the umbilical groove is wider and larger ; the coloration, too, is 

 quite unlike. Dr. J. Gwyn Jeffreys claims this species for his 

 genus Hela ; or Cithna, as he now proposes to call it, Hela having 



