OCR Text |
Show 1892.] LAND-SHELLS OF ST. HELENA. • 261 lens it is seen that they are variegated with irregular radiating blotches of red and white intermingled. The lines of growth are distinct, finely hair-like, arcuate and oblique on the upper surface, and gently undulating on the body-whorl. The umbilicus is deep but narrow, equalling about one fifth the diameter of the base. 3. PATULA DIAN.E (Pfeiffer). (Plate XXI. figs. 2-2 b.) This species does not belong to the group Hyalina ( = Vilrea), as supposed by Wollaston, but falls naturally into Patula together with the preceding species, which it very closely resembles. Hab. Diana's Peak. Living (Pfr.). 4. PATULA PERSOLUTA, sp. nov. (Plate XXI. figs. 3-3 b.) Testa minuta, late et aperte umbilicata, discoidalis, planorbi-formis, pallide rufescens (?) ; anfractus 3^,perconvexi, sutura profundissime discreti, subceleriter accrescentes, lineis incre-menti obliquis striati, ultimus tubiformis, rotundatus, antice solutus et descendens; apertura subcircularis, margine colu-mellari leviter planato. Diam. mag. 3 | millim., min. 2f, alt. 2. Hab. Side Path (Turton). Extinct. This is a very remarkable little species, at once recognizable by its Planorbiform appearance, and the detached anterior portion of the body-whorl. The upper whorls do not rise above the last, and the suture is remarkably deep. The umbilicus is very wide and open, permitting the convolution of the whorls to be observed to the apex. Both of the specimens examined exhibited traces of reel towards the apex, and there is every probability of the living shell having exhibited more or less of that tint. 5. PATULA L^ETISSIMA, sp. nov. (Plate XXI. figs. 4-4 b.) Testa minuta, anguste umbilicata, depresse subconoidea, alba, maculis radiantibus rufis supra et infra picta ; anfractus 5|, lente accrescentes, superne convexiusculi, sutura subprofunda sejuncti, lineis incrementi fortibus striati, ultimus ad peripheriam rotundatus, antice haud descendens ; apertura semi-lunata, edentula ; peristoma tenue, simplex, margine columel-lari dilatato ; umbilicus profundus, angustus, diam. totius 4 adesquans. Diam. maj. 4 millim., min. 3|, alt. 2g. Hab. Sugarloaf Ridge, near the top (Turton). Extinct. This little species is remarkable for its small deep umbilicus, the toothless aperture, rather well-marked lines of growth, the rounded periphery to the body-whorl, and the red colour-markings. These consist of radiating blotches on the upper surface of the whorls, which become rather angular and wavy on the middle and lower part of the body-whorl. |