Report on the zoological collections made in the Indo-Pacific Ocean ...

40 COLLECTTONS FROM MELANESIA.transverse lirje are nodose on crossing the ribs, tliree in numbernpon the upper whorls, a fourth being present upon the lower partof the penultimate and sixteen to eighteen on the last. Anotherfeature worth noticing is the presence of a finer thread-like lineabove the uppermost of the chief lirse, which runs in a slight concavityat the upper part of the whorls.The aperture is narrow, as is the shell itself, not greatly contractedat the canal, and occupies rather less than half the length of theshell. The columella is subperpendicular, a little tortuous andsmooth, without lira; or tubercles. The outer lip is thickened withan exterior rib, but thin and sharp at the extreme margin. It iswidely and semicircularly notched above just below the suture inthe faint concavity of the whorl, and generally in adult shells bearsa small tubercle within close to or just below the sinus, with whichexception it is smooth.8. Pleurotoma (Daphnella) axis.Plem'otoma axis, Reeve, Conch. Icon. fig. 311.Hah. Port Molle, 14 fms. (Copjyinger) ; Philippines (Cuming).The apical whorls of this, as in all the other species of thegroup Daphnella, are microscopically cancellated by oblique crisscrosslines. The four or five succeeding volutions are coarsely cancellatedby longitudinal costse and spiral ridges, the points of intersectionbeing subnodose. Beyond this the remaining whorls (aboutthree in number) are destitute of the costse, exhibiting only spiralridging of different degrees of fineness and intermediate finer striaecrossed only by the lines of growth.One of these ridges towards the upper part of the whorls isespecially prominent, giving them a somewhat shouldered appearauce,and between this and the upper thicl-ened margin there is a decidedconcavity. The aperture is elongate, contracted anteriorly into adistinct and somewhat recurving canal, together occupying a littleless than half the total length of the shell. The labrum is a triflethickened, presenting exteriorly a slightly swollen appearance, hasa rather deep slit above at the suture, is smooth within, and crenulatedfinely along the edge.9. Pleurotoma (Daphnella) arafurensis. (Plate IV. fig. G.)Shell fusiform, whitish, faintly banded with light brown, spirallyridged and striated and marked with the flcxuous lines of growth.Whorls 7 ; two apical globose, microscopically reticulated, but appearingsmooth under an ordinary lens, rather large ; the remainingfive are convex, a little constricted beneath the suture, andspirally ridged and striated. The upper whorls have four or fiveprincipal linr, the uppermost falling just beneath the slight constriction,and the others below at equal distances. The whorls arethickened at or immediately under the sut'jral line with an elevated