January, 1915. 



KNOWLEDGE. 



29 



the stable end-product of thorium) is 04 time the uranium 

 rate. If that assumption were true, then it would be 

 expected that in these minerals the ratio of lead to (uranium 

 plus 0-4 thorium) would be constant. As a matter of fact, 

 they find that this ratio is variable, and consequently they 

 conclude that lead is not the stable end-point of the thorium 

 series. The suggestion is made that bismuth is the end- 

 product of the thorium series, and that thallium is that of 

 the actinium. Such evidence as is available does not tend, 

 in the present writer's opinion, to support this view. 



ZOOLOGY. 



By Professor J. Arthur Thomson, M.A., LL.D. 



JOURNEYS OF LIMPETS.— Without troubhng himself 

 with the records of previous obser\'ers, which he has not 

 read, G. Billiard describes his observations of a particular 

 shore pool. He marked a number of limpets, and had the 

 satisfaction of pro\Tng that they went on the prowl for 

 several yards and returned. They do not go on a journey 

 when the sun is sliining on the pool, but wait for dull 

 weather or a shower. 



PEDIGREE OF BIRDS.— Following Abel ui part, 

 Baron von Huene suggests that birds arose from Ornithischia 

 at the stage of bipedal hopping creatures with backward 

 turned pubes and other specialisations. They became 

 climbers on trees ; they acquired skin expansions or 

 patagia, and practised swooping ; they subsequently 

 acquired feathers ; and ultimately learned true flight. 

 But we cannot yet tell how a Silver \\'yandotte evolved 

 from a Jungle Fowl ! 



REMARKABLE SEX DIMORPHISM.— Allan R. 

 McCulloch calls attention to frwo Australian Pipe-fishes, 

 Stigmatophora argiis and S. nigra, in both of which the males 

 carry the eggs in pouches, as is usual in the family Syn- 

 gnathidae. But, wliile there are no very strildng differences 

 in the form of the body in the two sexes of S. ai-gits, the 

 male and female of S. nigra are so dissimilar in their appear- 

 ance that one can only be sure of their specific identity 

 after a critical comparison of all their characters. The 

 male is sub-cylindrical and almost without ornamentation, 

 while his mate is broad and depressed, with rich pink and 

 black markings. 



HAIR OF C.\T. — Like many other mammals, the cat 

 has three kinds of hairs. They have been recently studied 

 in great detail by Dr. Hermann Hofer : (1) There are the 

 long, strong, prominent hairs, never wavy, ending in a fine 

 point. (2) There are shorter, wavy hairs, with alternate 

 broader and narrower portions, ending in a more abrupt 

 point. (3) There are woolly hairs, delicate, fine, and un- 

 dulating, with very little pigment. The three kinds of hair 

 differ markedly in their covering of cuticular cells. In the 

 unborn kitten the hairs occur in obvious groups of three — 

 a median hair and two lateral hairs. Later on, the lateral 

 hairs increase in number, and they are accompanied by 

 accessory hairs. The groups are disposed in longitudinal 

 rows. The median hairs become (1), the lateral hairs (2), 

 and the accessory hairs (3). 



FAUNA OF COAL-PIT AT GREAT DEPTHS.— Dr. 

 James Ritchie reports tliirteen different species at a great 

 distance from the surface, and notes that these probably 

 represent only a fraction of the denizens of the pit. Their 

 chief interest is in illustrating the " toughness " of life and 

 the early stages in the formation of a cave fauna. The 

 collecting-ground was at a depth of se\cn hundred and 

 fifty feet at Niddrie, in the Midlothian Coalfield. There 

 was no adjacent ventilating shaft to the surface, and the 

 main shaft was about a quarter of a mile away, ilost of 

 the animals must have come in wth the props of Norwegian 

 fir, which support the roof and walls of the working, and with 

 the horse fodder. Some of the light-bodied creatures may 



have been swept in by the ventilating currents. No special 

 modifications were observed. The list includes .^ The 

 Common Mouse, the Brown Rat, the House-sparrow, the 

 Great Slug [Liniax niaximus), a Small Spider [Lessertia 

 denticheiis), two Beetles, two Flies, a Springtail or " Pit- 

 fiea " [Tomocevus minor), two Earthworms [Eiseniella 

 letraedra and Helodnius [Dendrobacna] rubidus), and 

 a Mycetozoon [Stremo)iitis fusca) on the pit props. 



A BIRD IN A SPIDERS WEB.— In a letter to Professor 

 Poulton from the islands in the north-west of the \'ictoria 

 Nyanza Dr. G. D. H. Carpenter writes [Trans. Entomo- 

 logical Soc, 1914, Part II) : " Several islands have an un- 

 pleasantly large number of enormous spiders' webs, in which 

 I have seen a sun-bird caught fast. The webs form sheets, 

 stretching across open spaces from tree to tree, and not 

 in one plane only. Numbers of them are spun one behind the 

 other so closely that one wonders how on earth the owners 

 of the middle webs ever get anything to eat ! And, indeed, 

 many of them look half-starved ! Yet, on other islands 

 near by, the species seems hardly able to hold its own : it 

 is just there, and that is all one can say." 



DINOSAURS NOT A NATURAL ORDER.— In 1888 

 Seeley maintained that Owen's order Dinosauria should be 

 split into two, Sauriscliia (=Theropoda-f Sauropoda) and 

 Ornitliischia. Baron von Huene has recently corroborated 

 this view, and maintains that the Dinosaurs are not mono- 

 phyletic. The Sauriscliia and Ornithischia differ markedly 

 as to hip-girdle and skull. Moreover, in the vertebral 

 column, Saurischia of the highest degree of specialisation 

 do not possess ossified tendons as do all bipedal Ornithischia, 

 a difference probably correlated with different ways of 

 feeding and moving. Abdominal ribs are not known in 

 Ornithischia. Von Huene maintains that Saurischia and 

 Ornithischia came from the Pseudosuchia, the former directly 

 from their most primitive representatives by minor special- 

 isations, the latter from nrost advanced representatives by 

 a stage of bipedal hopping creatures, in which the pelvis 

 became adapted to this new locomotion by a turning back 

 of the pubis, as in birds, and the development of a praepubis. 



PORPOISES IN CAPTIVITY. — The New York 

 Aquarium is unique in having a school of Poi-poises (Tur- 

 siops tnmcatiis) living in captivity in good condition. The 

 Director, Mr. Townsend, has made some interesting observ- 

 ations on their habits. They are quieter at night, but they 

 seem to swim continuously. " A Porpoise, speeding 

 around the pool, can make a right-angled turn as quickly 

 as a frightened fish without lessening speed." All food is 

 swallowed under water, but they often play with a dead 

 fish, throwing it away for five to ten feet and catching it 

 again. They often appear to play, " darting with mock 

 ferocity after each other. ' ' The ordinary swimming motion 

 of the tail is up and down, but there seems sometimes to 

 be a side action. The fhppers are used in turning move- 

 ments. They often swim on their backs. There is consider- 

 able mobility of the short neck. There is no evidence that 

 they can see out of water. Mating was observed in January 

 and again in March and April, and the Director has some 

 expectation that they may breed. The five Porpoises in 

 the Aquarium consume about ninety pounds of fresh fish 

 in a day. The average length of this Dolphin is about eight 

 feet, and the average weight about three hundred pounds. 

 The species, Ttcrsiops truncatiis, or Bottle-nosed Porpoise, 

 has a wide distribution, occurring in many parts of the 

 North and South Atlantic and the Mediterranean, as well 

 as in the Indian Ocean and off New Zealand. 



CURIOUS HABIT OF COCKATOOS.— W. W. Froggatt 

 has some interesting notes on the Rose-coloured Cockatoo, 

 or Galah [Cacatua roseicapilla), of New South Wales. ^Vhen 

 they come to slake their thirst at the water-holes they are 

 fond of alighting on any post that may be in the water, and 

 it is a curious sight when half a dozen together crawl down 

 it to drink and stand on their heads. They have a quaint 



