M. Vrolik on the Anatomy of the Pearly Nautilus » 173 



than the rest. The perigonia are reniform or nearly round, and 

 fixed to the side of the stem by a very short peduncle. The pe- 

 richsetial leaves have but few large and obtuse teeth. The calyx 

 rises from a narrow base into an obcordate form. The calyptra 

 is colourless except at the summit, about the base of the style, 

 where it has the reddish-brown hue of the leaves. The capsule is 

 globose, 4-valved, and in all respects like that of Jung. Tamarisci. 

 From this last, Jung, fragilifolia may be readily distinguished, 

 — 1. by the wider cellulation of the leaves; 2. want of lustre; 

 3. fragility of the wet leaves ; 4. larger auricles in proportion to 

 the leaves ; 5. the plane margins of the stipules; 6. the greater 

 relative size of the perigonia to the plant ; 7. the large and obtuse 

 teeth of the perichsetial leaves ; and 8. by the abnormal cellules 

 being much larger. 



JuNGERMANNiA GERMANA, MSS. T. T. Caulc procumbente, bipin- 

 natira ramoso ; ramis complanatis, brevibus, patentibus : foliis im- 

 bricatis, ovate -rotundatis, integerrimis ; auriculis oblongo-ovatis, 

 ventricosis ; stipulis obovatis margine recurvis, apice bifidis ; foliis 

 perichaetialibus integerrimis ; calyce oblongo-ovato, tubifero ; pe- 

 rigonio lineari-ovato. 

 On rocks and on trees ; very common near Dunkerron, county of 



Kerry, 1832. 



The plant is three inches and sometimes more in length, and 

 matted into patches sometimes a foot in breadth. It is never so 

 black or so shining as Jung. Tamarisci. The fertile stems are 

 longer, more branched and more fastigiate ; whilst those bearing 

 perigonia are far narrower and with shorter branches. The leaves 

 are thin, and do not present the linear mark of enlarged opake 

 cells as in Jung. Tamarisci. The stipules are wider than the 

 stems, and the recurvation of their margin chiefly observable to- 

 wards the summit. The margins of all the perichsetial leaves are 

 quite entire. The perigonium is a linear spike as in Jung, dila- 

 tata, Hook. 



A very common species, hitherto confounded with Jung. Ta- 

 marisci, but readily distinguished when attention is paid to the 

 * ntire perichsetial leaves, to the linear perigonium, as well as to 

 the lighter colom* and want of lustre of the leaves. 

 1- 



XXII. — On the Anatomy of the Pearly Nautilus. Communicated 

 by W. Vrolik, Professor of Anatomy in Amsterdam. 



To the Editors of the Annals of Natural History. 



Gentlemen, Dublin, July 27, 1843. 



I PRESUME that it will be agreeable to you to receive some de- 

 tails on the anatomy of the Pearly Nautilus [Nautilus Pompilius), 



