margin is thin, angular b) the terminations of the spiral keels; columellar margin strongly 

 excavated above, thi ing bordered by the strong toothlike projection forrned at 



the end of the umbilii ' the appearance oi a compressed fold; below this tooth, 



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

 the slightl) curved basal margin. Interior nacreous. 



Alt apert. alt. 2'/ t , lat. i ',.. ; diam. of umbilicus about , Mill. 



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

 one, the " ( :: ^ slightly differ by the number and disposition of the basal spirals, and 



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



rly wanting and are, for instance, reduced to 1 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 

 chara ire really the same, 1 think these ditïerences will prove to be individual. I maybringin 



■mbrance what Dall says (Buil. Mus. Comp. Zool. Vol. XVIII, p. 269), dealing on Seguenzia: 

 -Hithcr 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, thcir strength and sharpness on the basal disk. 

 are entirely inconstant". 



This species seems to be nearly allied to S. elegans Jeffr. (Proc. Roy. Soc. 1876, p. 200, 

 Proc. Zool. Soc. Lond. 1885, p. 42, PI. 5, fig. 1, ia) 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 ditïerences in specimens from 

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



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



Stat. 241. 4° 24.3 S., I2Q°49'.3 E. Banda Sea. 1570 M. Dark sand with smal! stones. 1 Spec. 



Shdl 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 



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



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



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, 



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



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



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



72 



