i8o 



outer margin is thin, angular by the terminations of the spiral keels; columellar margin strongly 

 excavated above, this excavation being bordered by the strong toothlike projection formed at 

 the end of the umbilical groove, it has the appearance of a compressed fold; below this tooth, 

 the columellar margin runs obliquely back and terminates in a projecting point where it joins 

 the slightly curved basal margin. Interior nacreous. 



Alt. 475, lat. y/i.\ apert. alt. 2^4, lat. i-/g; diam. of umbilicus about "/o ^i^^- 

 This description is made after the specimen from Stat. 178, which was the most complete 

 one, the other specimens slightly differ by the number and disposition of the basal spirals, and 

 more considerably in the finer spirals of the interstices between the keels, which in some parts 

 are nearly wanting and are, for instance, reduced to i and 3 in the spaces below the infra- 

 sutural spiral and above the peripheral keel in the specimen from Stat. 88, as however all other 

 characters are really the same, I think these differences will prove to be individual. I may bring in 

 remembrance what Dall says (Bull. Mus. Comp. Zool. Vol. XVIII, p. 269), deahng on Segtienzia: 

 "Either each separate individual is to be regarded as a species, or the variability is very great. 

 Persistant study of the specimens has convinced me, that the latter is the true solution, and that 

 the most evident characters, such as the umbilicus (in some adult specimens) may be present 

 or absent, that the number of spiral threads, their strength and sharpness on the basal disk, 

 are entirely inconstant". 



This species seems to be nearly allied to S. elegans ]&^x. (Proc. Roy. Soc. 1876, p. 200, 

 Proc. Zool. Soc. Lond. 1885, p. 42, PI. 5, fig. i, \d) but the radiating sculpture in the new 

 species is much less crowded and coarser, the same is the case with the basal spirals, the new 

 species is less flattened below the suture, more conical etc. These differences in specimens from 

 such a remote provenience, have induced me to consider them as specifically distinct. 



3. Seguenzia Sykesi n. sp. PI. XII, fig. 6. 



Stat. 241. 4°24.3S., 1 29° 49'. 3 E. Banda Sea. 1570 M. Dark sand with small stones, i Spec. 



Shell small, subglobose, spire forming a short, subgradate cone ; umbilicate, whitish-yellow, 

 with a slight nacreous lustre. Whorls about 6, of which about one forms the blunt, smooth 

 nucleus; the next whorls, including the penultimate, have only one strong median keel, the 

 space above and below this keel is slightly concave, with a few microscopic spiral threadlike 

 striae; two whorls next to the nucleus are crossed by conspicuous radiating riblets, straight but 

 in an oblique direction above the keel, convex below it, these riblets then suddenly disappear, 

 only very fine striae succeeding them, being scarcely perceptible on the last whorl, with is 

 bicarinate; a third keel borders the flattened base; suture rather conspicuous but shallow, with 

 very slight traces of being margined, probably by the covered keel ; base with 7 spirals of which 

 the distal one, separated from the third keel by a slightly concave space, and one bordering 

 the umbilicus are stronger; moreover the whole base is covered with microscopic radiating striae, 

 beautifully waved in an S-like manner. Umbilicus moderately wide, pervious, funnel-shaped, 

 its wall wave-striated, with a shallow spiral groove terminated by a tooth on the columella. 

 Aperture irregularly subquadrate, its outer margin so much broken, that no sinus remains, it 



72 



