446 



This species, according to Mr. Melvill, is allied to D. eulime7ies Melv. (Journ. of Mai. 

 1904, Vol. XI, p. 84, PI. 8, fig. 15), but different; the Siboga-shell is considerably less slender, 

 more angular, the excavation is much larger and the sculpture coarser. 



5. Pleurotomella clathtirellaeformis n. sp. PI. XXX, fig. 4. 



Stat. 178. 2°4o'S., 128° 37'. 5 E. Ceram-sea. 835 M. Blue mud. 2 Spec. 



Shell elongately-fusiform, thin, transparent, white. Whorls about 9, of which about 3 

 form a reddish-brown nucleus, composed of convex whorls, with riblets in different directions, but 

 the nucleus being rather worn, the sculpture is not prominent. Subsequent whorls convex, with 

 a narrow, excavated part below the deep suture; the excavation is crossed by numerous, slightly 

 curved, axial riblets. The convex part of whorls is sculptured by strong, rounded, oblique, 

 axial ribs, 1 1 in number on last whorl, crossed by strong spirals, 6 in number on penultimate 

 whorl, of which 4 are stronger and are especially prominent on the crest of axial ribs; these 

 ribs disappear on the base of last whorl, which, as well as the rather short canal is lirate. 

 Aperture oval, angular above, ending below in a rather narrow, slightly curved, compressed 

 canal; peristome thin, with a narrow, shallow sinus above; columellar margin concave, with 

 a thin layer of enamel, directed to the left near the canal. 



Alt. 8Y4, lat. 3; apert. alt. 3^4, lat. i Mill. 



As the nucleus was not in perfect condition, the generic position seemed to be some- 

 what doubtful, but the contrast in colour, between nucleus and rest of shell, the riblets below 

 the suture and other characters it has in common with the preceding species, have at last given 

 the decision. 



6. Pletirotoniella exteiisaeformis n. sp. PI. XXX, fig. 5. 



Stat. 212. 5°54'.5S., 120° 19'. 2 E. Banda-sea. 462 M. Fine grey and green mud. i Spec. 



Shell ovate, with short spire, rather strong, ivory-white. Whorls 8 or 9 (upper part 

 eroded) of which 3 (or 4) form a reddish-brown, convexly-whorled nucleus, of which about 2 

 lower ones are sculptured by slightly curved riblets, crossed in their lower part by fine, oblique 

 striae. Subsequent whorls scarcely excavated, the place of the excavation being occupied for a 

 great deal by a rather strong, subsutural spiral, adorned by strong, laterally compressed beads, 

 22 in number on last whorl; below this spiral remains a rather large groove. Basal part of 

 whorls with narrow, a little oblique ribs, 1 5 in number on last whorl, ending below the groove 

 in short tubercles, which are connected by a second spiral ; the space between the ribs is sculp- 

 tured by fine and coarse growth-lines and faint spiral striae, becoming stronger and groovelike 

 towards the base of last whorl, and have the character of lirae on the short, large canal ; last 

 whorl regularly convex, until the canal. Aperture oval, with a moderately sharp angle above 

 and a wide, slightly gutter-like canal below ; peristome broken, probably with a very shallow 

 sinus (judging after growth-lines) ; columellar margin with a thin layer of enamel, concave. Canal 

 directed to the left. 



Alt. 8Y2, lat. 4Y2; apert. alt. 3, lat. 1Y3 Mill. ' 



82 



