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margins, it has a broad, triangular cusp, with one small median denticle and about 6 smaller 

 ones on each side; the laterals (i) one on each side, have a transversely triangular shape, with 

 an unarmed, arched upper and concave proximal and basal margin, with blunt points at the 

 proximal and distal extremities of the basal margin; on each side I see at least 3, but I suppose 

 there are 4 uncini (U) which are long, slender and strongly curved. Though this radula has 

 some resemblance with that of Aporrhais, like Verrill (Mollusca of the New England coast, 

 Transact. Connecticut Acad. of arts and sciences, Vol. VI, May 1884, p. 186 and 188) has stated, 

 and like his figure (1. c. pi. 31, fig. 14^) affirms, I cannot agree without doubt with his view 

 that it should be Taenioglossate, as the "Siboga"-specimen has a radula with at least 9 rows 

 of teeth and probably 11. The nacreous character of the shell agrees with the Rhipidoglossa, 

 and so does the larger number of uncini. I should think the genus will belong to the Rhipi- 

 doglossa with a restricted number of teeth, such as Basilissa. As however only a knowledge 

 of other anatomical particulars, the position and structure of the gills, of the heart etc. can 

 decide the question I have left the family near Trichotropis, in accordance with the newest 

 systematic arrangement of Pelseneer (A treatise on Zoology, edited by Ray Lankester, Part V, 

 Mollusca, 1906, p. 156. 



2. Seguenzia Datitzeuöergi n. sp. PI. XII, fig. 5. 



Stat. 88. o°34'.6N., H9°8'.sE. Makassar Strait. 1301 M. Fine grey mud. 1 Spec. 



Stat. 178. 2°4o'S., I28°37'.5E. Ceram Sea. 835 M. Blue mud. 1 Spec. 



Stat. 211. 5°4o'.7 S., i20°45'.5 E. Banda Sea. 1 1 58 M. Coarse grey mud. 1 Spec. 



Shell rather small, spire forming a short gradate cone, umbilicate, whitish-yellow. Whorls 

 7, of which the uppermost forms the smooth nucleus, foliowed by about 2 whorls with a sub- 

 median keel and displaying a cancellated appearance by the intercrossing of subequal spiral and 

 radiating riblets. The other whorls have each 3 spirals, of which the uppermost runs at a little 

 distance from the suture, the next which is the strongest, renders the whorls carinate about 

 halfway, and a third which seems to run just in the rather conspicuous suture-, moreover the 

 interstices have more or less numerous fine spirals (numerous in the type, where they quite fill 

 the spaces) ; this spiral sculpture is crossed by radiating riblets, running straight in an oblique 

 direction, from the suture to the upper spiral, where they form small crenulations, in the next 

 interstice they are concave and at last convex towards the basal liration; last whorl rounded, 

 with a strong peripheral keel, being the basal one of the upper whorls, and a convex base, 

 with another spiral at some distance from the peripheral keel, and 1 2 basal spirals of which 

 three more spaced ones, at a larger distance from the subperipheral spiral, and 9 more central 

 spirals, which are flatter, at subequal distances, the innermost bordering the umbilicus; these 

 spirals are connected by small radiating riblets in the interstices, moreover these interstices are 

 filled, as far as I can see, with similar finer spirals as in the spire. Umbilicus moderately wide, 

 probably pervious, funnel-shaped, its wall with fine radiating striae and a conspicuous spiral 

 groove, terminating in a strong dentiform projection on the columellar margin. Aperture moderately 

 large, irregular in shape, with a rather deep sinus at the suture (about i 1 /, Mill, behind the 

 most projecting part of the outer margin), it is rounded behind, with an upturned margin ; the 



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