Seila.] GASTROPODA. 251 



the marginals, higher than wide, have 2 denticles at the point, which 

 is less than half as wide as the base. Formula f + l+i+i+f- (Ball.) 



Shell small, fragile, subcylindrical, narrow. Spire long, subulate. 

 Protoconch paiicispiral, with a mamillate nucleus, whorls imbricate 

 anteriorly and spirally lirate. Whorls flat, with prominent spiral 

 keels, trellised in the interspaces by fine, crowded growth-lines, which 

 leave no trace on the keels ; last whorl but little elevated, carinated 

 at the periphery of the base, which is flattened or even excavated ; 

 ornamented with radiate sinuous plications, extending to the edge of 

 the canal, which is formed by growth of the basal notch, and replacing 

 the neck, which is completely absent. Aperture subquadrangular. 

 with a short truncated canal below. Outer lip thin and sharp. Colu- 

 mella very little arcuate. Operculum shaped like a Carinaria shell in 

 outline, but somewhat narrower, with the apex free, pointed, and 

 turned to the left. The attached surface is deeply concave. 



Distribution. Tropical, subtropical, and temperate seas. 



Fossil. From the Cretaceous. 



KEY TO SPECIES. 



A. Penultimate whorl with 3 cinguli. 



a. Body-whorl with 4 cinguli and 1 on the base. 



b. Protoconch of 1 whorls, bulbose . . . . bulbosa. 



bb. Protoconch of 4 whorls, not bulbose . . . . terebelloides. 



aa. Body-whorl with 4 cinguli, none on the base . . . . dissimilis. 



B. Penultimate whorl with 4 cinguli. 



. Body-whorl with 5 to 6 cinguli, and 1 on the base . . chathamensis. 



aa. Body-whorl with 5 cinguli, and 2 on the base . . cochleata. 



1. Seila bulbosa, Suter, 1908. Plate 14, fig. 25. 

 Seila bulbosa. Suter. P. Mai. S., viii, 37, pi. 3, f. 46. 



Shell small, elongate, many-whorled, with a bulbose apex, rather 

 solid. Sculpture : The first 1^ whorls smooth, the following volutions 

 with 3 narrow and rather sharp spiral keels, the upper 2 closer together, 

 last whorl with 5 keels, the lowest of which is upon the base ; in- 

 terstices having fine, dense, straight growth-lines, sometimes oblique 

 near the suture. Colour white. Spire much higher than the aperture ; 

 outlines straight. Protoconch globular, of 1J smooth whorls, the first 

 bulbose, of greater diameter than the next few whorls. Whorls 

 about 14, slowly and regularly increasing, flat ; base slightly concave. 

 Suture very little impressed. Aperture subquadrangular, produced 

 below into a short and open canal. Outer lip sinuated on the outside. 

 Lower lip horizontal, slightly ascending toward the canal. Columella 

 short, nearly straight, bent over, and ending in a point below ; parietal 

 wall lightly excavated. Operculum unknown. 



Diameter, 3 mm. ; height, about 13 mm. No perfect specimen 

 available. 



Animal unknown. 



Type in my collection. 



Hob. Snares, in 50 fathoms (Captain Bollons). 



