March, 1915. 



KNOWLEDGE. 



69 



It wall be noticed that these curves are of verv 

 similar shape for sodium, potassium, rubidium, and 

 caesium, but the Uthium line curves slightly in 

 the opposite direction to the sodium line. This 

 difference corresponds to the difference of sign in 

 the formula. The straight line on the left, marked 

 hydrogen (principal series), represents a series of 



three lines in hydrogen observed by Professor 

 Fowler. It is further to be noticed in this diagram 

 that the convergence-frequencies of hydrogen, 

 lithium, sodium, potassium, rubidium, and caesium 

 lie in the order of the atomic weights of these 

 elements, namely, t, 7, 23, 39, 85-45, and 132-81 

 respectively. 



[To be continued.) 



MALE BIRDS WITH FEMALE PLUMAGE. 



It is not at all an uncommon thing for hen birds, 

 owing to old age or injury, to begin to assume the 

 plumage of the cock, and an interesting case has 

 been described in our columns (see " Knowledge," 

 Volume XXXVI, January, 1913, page 7) of a hen 

 Ostrich which, when its ovaries were removed, 

 developed male plumage entirely. The reverse 

 case, however, is rare. We give here a photo- 

 graph of a stuffed specimen of the Common 



Pheasant in Eton College Museum, which came from 

 the Millais Collection, in which the tail feathers, 

 though of the length usually found in the male, 

 are coloured and marked like those of the female. 

 Figures 61 to 64 illustrate this point very well. 

 There are also certain feathers on the sides of 

 the bird which, instead of being brilliantly coloured 

 like those of the cock, are sober-hued like those of 

 the hen. \v. m. W. 



THE ZOOLOGICAL SOCIETY 



At the scientific meeting of the Zoological Society, 

 held on February 9th, Sir Edmund G. Loder, 

 Bart., F.Z.S., exhibited the tanned skin of a large 

 Capybara (Hydrochoerus hydrochoerus) , which he 

 suggested might be identical with the " pigskin " 

 of commerce, and the skull of a Walrus [Trichechus 

 rosniarus) from Kamschatka, with record tusks. 

 The weight of the skuU and tusks was about 

 forty pounds. The tusks alone weighed twenty-one 

 and a half pounds, and measured thirty-six and 

 a half inches in length, tw^enty-nine and a half 

 inches from outside the gum, and nine and live- 

 eighths inches in girth. 



Dr. P. Chalmers Mitchell, F.R.S., F.Z.S., Secre- 

 tary to the Society, exhibited preparations of the 

 stomach and intestines of the Open-bill {Anasiomus 

 oscitans), and described the elaborate sifting 

 apparatus in the stomach and the presence of 

 only a single colic coecum. 



Mr. E. Heron-Allen, F.L.S., F.Z.S., exhibited 



a series of skiagraphs of Foraminifera, revealing 

 their internal structure without transparent mount- 

 ing or section-cutting, or other interference with 

 the specimens, and illustrating the application of 

 .v-rays to microscopical research. 



Mr. Guy Aylmer, F.Z.S., exhibited some skins 

 of mammals from Sierra Leone, including those of 

 a Serval [Fclis capensis) and of a Servaline Cat 

 (F. servalina), and stated that a native had brought 

 him two kittens, almost certainly from the same 

 litter, one being spotted like the Serval, and the 

 other obscurely speckled like the Servaline Cat. 

 This he regarded as proof that the differences 

 between the Servals and Servaline Cats are of no 

 systematic importance. 



Mr. E. G. Boulenger, Curator of Reptiles, read 

 a paper on an Aglyphodont Colubrid Snake 

 [Xenodon merremii), with a vertically movable 

 maxillary bone. 



FLORA SELBORNIEXSIS. 



March, Third Month [Continued). 



11th. — The Dandelion is Taraxacum dens-leonis. 



The Sycamore, as we now spell it, is Acer pseudoplatanus. 



12th. — The Furze [Ulex europaeus) is one of the plants that may be found in flower at all times of 

 the year. 

 Dog's Mercury is Mercurialis perennis. Birch is BeftUa alba ; the Wood Laurel, Daphne 

 laureola. The Humble Bee, if it is a species of Bombylius, should be Humble-bee Fly. 

 The names of the other plants mentioned under this date are : Vinca minor ; Alliaria 

 officinalis ; Senecio jacobaea ; Cynoglossum officinalis ; Malva sylvestris, which still stands ; 

 Nepeta glechoma (Ground Ivy) ; Asperula odorata ; and Daphne mezereum. 



