Mr. A. Adams on new Mollusca from Japan. 331 



the inner, cc c, represent the section of the netted cylinder ; 

 b, origin of a rootlet. 



Fig. 6. Cross section of the rhizome of Lastrea Oreopteris, somewhat fore- 

 shortened, with a portion of a petiole attached, showing the con- 

 verging tracts of dark tissue, a. 



Fig. 7- Section of the rhizome of Lastrea dilatata along the axis, showing 

 the fusiform dark nodules in the medullary tissue : a a, fasciculi 

 of the netted cylinder in section. 



Fig. 8. Cross section of a petiole of Asplenium Ruta muraria near the 

 base. 



Plate VI. 



Fig. 1. Section of the petiole of Scolopendrium vulgare, along the axis, 

 showing the course of the dark tracts, like two converging lines 

 of railway. 



Fig. 2. Cross section of the same, a little above the base. 



Fig. 3. Cross section of the same, about the commencement of the lamina 

 of the frond. In the small fronds of Ceterach officinarum the 

 arrangement is somewhat similar. 



Fig. 4. Cross section of the petiole of Athyrium Filixfoemina at the base. 



Fig. 5. Cross section of the rhizome of Hymenophyllum Wilsoni, showing 

 the brown cortical and pale medullary tissue, with the single 

 vascular fasciculus imbedded in the latter. 



Fig. 6. Cross section of the rhizome of Allosorus crispus, showing the 

 central dark cord, and the sheaths round the fasciculi of the netted 

 cylinder. 



Fig. 7. Cross section of the rhizome of Pteris aquilina, showing the outer 

 and inner series of vascular fasciculi, the two intermediate dark 

 bands, and the extremities of some of the longitudinal dark fila- 

 ments. 



Fig. 8. A corresponding section of the base of the petiole. 



Fig. 9. Cross section of the petiole of Polypodium alpestre above the point 

 of junction of the two lateral fasciculi. The section below this 

 point is nearly as in fig. 4. These two figures would also repre- 

 sent in some degree the arrangement in Lastrea Thelypteris, if 

 the fasciculi were surrounded by a coat of dark tissue. 



Fig. 10. Cross section of the petiole of Lastrea cristata near the base. 



There is a similar arrangement in Polystichum aculeatum, 

 Lastrea Filix mas, and L. dilatata, and also, with the exception 

 of the dark sheaths, in Polystichum Lonchitis. 



The magnifying power is marked beside each figure. 



XLII. — On some new Genera and Species of Mollusca from Japan. 

 By Arthur Adams, F.L.S., &c. 



Genus Zafra, A. Adams. 



Testa acuminato-ovalis utrinque angustata, in medio tumida ; anfrac- 

 tibus longitudinaliter plicatis, ultimo ad basin constricto. Apertura 

 linearis, angusta ; labio effuso, margine externo libero ; labro mar- 

 gine acuto, postice subsinuato, in medio recto, subinflexo. 



This little shell will constitute the nucleus of a group of Tur- 

 ridce, of which several from deep water have been described by 

 D'Orbigny, and figured, I believe, in the last plate of Reeve's 



22* 



