98 SELECTED NOTES FROM 



thrust in among the substance of the older strata, or from the 

 alteration of the pre-existing strata themselves. 



Granite consists of three minerals : quartz, mica, and felspar. 

 Syenite is of similar composition, except that the mica is replaced 

 by a greenish-black crystalline mineral called horne-blende, seen in 

 the section as greenish crystals. Felspar occurs in crystals which 

 have a somewhat elongated form and ragged outline, due to their 

 being crossed in two directions by cleavage planes. One set of 

 cleavage planes (the most conspicuous) is longitudinal ; the other 

 transverse. There are two varieties of felspar : orthoclase, in 

 which the planes are at right angles to each other, and plagioclase, 

 in which they lie obliquely. H. F. Parsons. 



Section Stenocarpus Cunninghami.— Stained by Dr. Beattie's 

 method. The anahne colours stain all too quickly ; yet the 

 details of the section cofitinue to come out much more plainly than 

 in others which have never been stained. 



The genus Stenocarpus is one of the Profeacecz, an order of 

 perigynous exogens, comprising some forty-live genera, nearly all 

 of them natives of the Cape of Good Hope or Australia — shrubs 

 or trees with hard dry leaves, often showy flowers, and often differ- 

 ing very much in external appearance ; hence the name of the 

 order. The present species is a lofty tree, with handsome orange 

 flowers in terminal umbels, and is found in Queensland and other 

 semi-tropical parts of Australia. The section is made from a small 

 twig of a tree growing in an English conservatory, and shows 

 under the microscope small sphgeraphides, and, also, both in the 

 centre and round the edge, numerous angular semi-opaque nodules 

 of very various sizes. Are these resinous or siliceous concretions ? 

 I do not remember to have seen any such in 7^/^^^ sections before, 

 though in many of the seeds of commerce they are not uncommon. 

 It would be useful to know if the wood furnishes any resinous or 

 other useful products. J. H. Green. 



J) 



EXPLANATION OF PLATES I., 11. , IIL, IV. 



Plate I. 



Fig. 1. — Represents some of the Sporangia of Platycerium alicorne, 

 with stellate hairs intermixed. 



. — Shows the various stages in forming Anchors and Anchor -plates 

 of Synapta inherens, after Wyville Thomson. The first stage 

 consists of minute calcareous granules (a) ; the anchors precede 

 the plates ; a slender rod is the first indication (6). By accre- 

 tion this enlarges somewhat, and grows out laterally on either 

 side of one end (c) ; by continuance of the process through 

 (d) the perfect state is nearly arrived at. In the meantime, 

 underneath the anchor — that is, nearer the interior of the 



