88 Notes and Comments. 



followed by a skiagraph of the same. A skiagraph of the still 

 denser test of Biloculina bulloides d'Orb. shows the arrangement 

 of the earlier chambers as clearly as it is indicated in Schlum- 

 berger's beautiful sections. The apphcation of X-rays to the 

 dense imperforate shells Cornuspira fdliacea (Phillippi) produced 

 skiagraphs showing the dimorphism of the shells, both megalo- 

 and microspheric primordial chambers being clearly distin- 

 guishable. Such results led to the extension of the experiments 

 to the agglutinated arenaceous forms, of which sections are 

 made with extreme difficulty. The skiagraph of Astrorhiza 

 arenaria Norman shows the internal cavities that contained 

 the protoplasmic body. Two arenaceous forms, Botellina 

 lahyrinthica Brady and Jaculella obtusti Brady, that are almost 

 identical in external appearance, are distinguished at once by 

 their respective skiagraphs, the one exhibiting a simple tabular 

 cavity, the other appearing labyrinthic. 



NUMMULITES, ETC. 



Mr. Barnard subsequently experimented on still more 

 difficult material. The massive Operculina complanata De- 

 france, the umbilical portion of which is obscured by a mass 

 of secondary shell-substance, furnished a clear skiagraph that 

 showed some curious distortions of the internal septa. Similar 

 results were obtained in the case of Orhiculina adunca (Fichtel 

 & Moll), another species overladen with shell-matter. Cyclam- 

 mina cancellata Brady is an arenaceous form, composed of 

 softer mud and sand, studded with coarse sand-grains which 

 make section-cutting almost an impossibility. The skiagraphs, 

 however, reveal the primordial chamber, and establish the 

 character of this form. The determination of the Nummulites, 

 depending as it does on a knowledge of the internal structure 

 of the test, is greatly facilitated by the application of X-rays, 

 which removes the necessity of splitting it or cutting sections 

 through it. The speaker showed ordinary photographs and 

 skiagraphs, made at slightly varying azimuths, of Nummulites 

 IcBvigata and N. variolaria, forms that strew the shores of Selsey 

 Bill. A particularly notable result was obtained in the case of 

 N. gizehensis, an organism that forms the dense masses of 

 Nummuhtic Limestone of which the Pyramids of Egypt and 

 the Citadel at Cairo are built. 



The Journal of the Marine Biological Association, Vol. XI., No. 3, 

 is quite up to the usual standard of the Journal we expect from this 

 useful Society. It is well illustrated, E. W. Sexton's drawing on plate 

 VII. being particularly pleasing. Besides the report of the Council, 

 the Journal contains ' The Loss of the Eye-Pigment in Gammarus chev- 

 veuxi, a Mendelian Study,' by J. E. Allen and E. W. Sexton ; ' Heredity 

 in Plants, Animals, and Man,' ' Food from the Sea," and ' The Age of 

 Fishes and the Rate at which they grow,' all by J. E. Allen. 



Naturalist, 



