552 Mr. J. C!. Mclvill on the 



euporne rotiinde angulatis, ultimo anfraotu circa novem costis 

 praedito, spiraliter arete bino lirarum ordine succinctis, interstitiis 

 inter costas caveruosis ; apertura ovato-oblonga, labro incrassato, 

 intus 4-5-denticiilato ; columella fere recta, omnino cinereo- 

 caerulcscente, lapidis fissilis colore prgesertim instar. 

 Ixmg. 18, lat. S'oO mm. 



Thougli shouldered just below the suture:^, the roundly 

 noduled ribs of this species, thickly crossed by thin spiral 

 lines, the interstices between the costaj being deeply cavernous, 

 amply characterize it. Indeed, we know no species nearly 

 comparable ; and another very special point of distinction is 

 the slate or dull indigo-coloured aperture, labial and coluraellar 

 area, which seems constant, being present, without any 

 deviation, in all the examples I have examined. The only 

 Sistriim at all comparable appears to be S. anaxares, Duclos, 

 formerly esteemed a Purpura. 



Natica [Eunatica] tela-aranece, sp. n. 

 (PI. IX. fig. 2.) 



N. testa subperforata, ovato-conica, solida, alba, castaueo-variegata ; 

 anfractibus 5, quorum apicales tres subvitrei, brunuescentes, 

 nitidi, perlaeves, caeteris ad suturas impressis, laevibus, infra (juxta 

 suturas) spiraliter flammis castaneis decoratis, inde ad basiu 

 intricatione intertexta notata, ultimo anfractu ca3tero3 magnopere 

 superante ; apertura luuari, albida ; peristomate albo, nitido, con- 

 tinue, subeffuso, margine coluraellari obliquo, albo-brunnescente, 

 callo nitido brunneo ; umbilicum profundum semiobtegente. 



Alt. 11, diam. 10 mm. 



Allied to N. Raynoldiana, Recluz, than which it is much 

 smaller, at the same tinie being differently marked and 

 coloured. Indeed, the pattern is intricate and somewhat 

 involved — a mesh of textile network, with occasional clear 

 spaces disposed spirally, giving an obscurely white-banded 

 effect, notably just below the sutures. The umbilicus is half 

 hidden by a shining brown callus, the peristome being white, 

 continuous, slightly effuse without. In the example taken as 

 the type the greater part of the body-whorl is dorsally without 

 the chestnut involved pattern ; no doubt this is accidental. 

 Another ally is N. sanctce-helence, E. A. Sm. ; both this, 

 N. Trailln, Reeve, and N. buriasensis, Recluz, show slight 

 points of relationship ; the brown callus of Traillii is similar, 

 but in all the pattern of marking is quite distinct, as also are 

 the apical whorls. 



