DUBLIN NATURAL HISTOKT SOCIETY. 129 



2 ad. Hexagonal cells, formed of adjoining prismatic figures, with 

 rectilinear axes, terminated by a truncated plane, at right angles to the 

 axes of the prisms. 



These cells are found in wasps' nests from St. Lucia, in the West Indies, and at Gra- 

 ham's 'lown, in South Africa, which were placed at my disposal for this investigation by 

 Mr. Robert J. Montgomery. 



3rd. Hexagonal cells, formed of adjoining prismatic figures, with 

 rectilinear axes, terminated by three faces of a rhombic dodecahedron, 

 which three faces also form, each, one-third of the termination of a similar 

 set of adjoining hexagonal prismatic cells, placed end to end behind the 

 first set of prisms. 



This double comb is produced by the well-known form of the cells of the honey-bee. 



All these varieties of cells may be accounted for, simply by the 

 mechanical pressure of the insects against each other during the forma- 

 tion of the cell. In consequence of the instinct that compels them to 

 work with reference to a plane, and of the cylindrical form of the 

 insects' bodies, the cells must be hexagons ; and in consequence of the 

 instinct that induces the bees to form double combs, the mutual pres- 

 sure of their heads against each other compels the bottom of the cell 

 to assume the form of the rhombic dodecahedron. If we could imagine 

 spherical insects endowed with the instinct of working from a point 

 and not a plane, their cells would cease to affect the forms of the hexa- 

 gon and rhombic dodecahedron, and would imitate the totally different 

 form of the pentagonal dodecahedron — instances of which may be seen 

 in the bubbles produced in the froth of an organic solution, and in the 

 shapes of the elementary cells of vegetables, equally restricted in their 

 growth in every direction — and also in the pentagonal faces assumed 

 by leaden bullets made to fill completely the inside of a hollow shell, 

 and then discharged against a bank of earth or a wall, from a mortar. 



On this subject, I cannot do better than quote the words of Buffon, 

 who was the first person that put forward a rational theory of the shape 

 of the cells of bees. The passage which I quote may be found in his 

 Histoire Naturelle, tom. iv. p. 99 : — 



" Dirai-je encore un mot ; ces cellules des abeilles, ces hexagons, 

 tant vantes, tant admires, me fournissent une preuve de plus contra 

 I'enthousiasme et 1' admiration : cette figure, toute geometrique et toute 

 reguliere qu'elle nous paroit, et qu'elle est en effet dans la speculation, 

 p'est ici qu'un resultat mechanique et assez imparfait qui se trouve 

 sou vent dans la N'ature, et que Ton remarque meme dans ses produc- 

 tions les plus brutes ; les cristaux et plusieiu's autres pierres, quelques 

 eels, &c,, prennent constamment cette figui'e dans leur formation. Qu'on 

 observe les petites ecailles de la peau d'une roussette, on verra qu'elles 

 sont hexagones, parce que chaque ecaille croissant en meme temps se 

 fait obstacle, et tend a occuper le plus d'espace qu'il est possible dans 

 un espace donne : on voit ces memes hexagones dans le second estomac 

 des animaux ruminans, on les trouve dans les graines, dans leurs 



