158 



NATURE 



[March 30, 191 1 



(jraham-White has a small biplane on show. This 

 machine has a span of 27 feet and an overall length of 

 Si feet, and is htted with a (Inome engine of 50 horsc- 

 ])ower driving a four-bladed propeller. On account of the 

 small span and chord, the machine is exceptionally fast, 

 and has been repeatedly flown in gusty winds of velocity 

 "P '0 35 niilfs per hour. .Muminium has been entirely 

 lispensed with in the construction, the whole of the fittings 

 and connections being of steel. The machine can be 

 sei)ar;ited into three sections for transport. 



The Hritish and Colonial Aeroplane Company, Ltd., 

 \hil)it three of their now well-known Bristol machines, a 

 military biplane, a racing biplane and a monoplane. 

 1 lie planes in the biplane type are so shaped— from experi- 

 mental evidence — that a considerable amount of lifting 

 power is in reserve under normal conditions of flight. The 

 (inomc engine is used by this firm, who are the sole agents 

 for it in Great Britain and the Colonics. 



The Sanders Aeroplane Co., of Beccles, Suffolk, and 

 I^ondon, exhibit a biplane having some novel features. 

 The extreme tips of the upper planes dip downwards, both 

 upper and lower planes being set at a dihedral angle. There 

 is a biplane elevator in front and a triplane rudder at the 

 rear. Balancing planes are placed between the main planes, 

 and no tail plane is fitted. The peculiar shape of the wings 

 is claimed to give great stability, even in high winds. 

 The main frame of this machine has diagonal braces con- 

 sisting of flat steel strips. The carriage comprises two 

 skids, and is fitted with two wheels which draw up under 

 the body when released by a trip device, enabling the 

 machine to alight on the skids alone. The outer portions 

 of the main planes are hinged to the central portion, and 

 may be folded inwards for convenience in storage and 

 transport. 



.'\mong historical machines shown by the Royal Aero 

 Club is the Bl«5riot monoplane on which Graham White 

 won the Gordon Bennett Cup at Belmont Park in October, 

 it)iO ; the Howard Wright biplane with which Sopwith 

 won the Baron de Forest prize of 4000/. by a flight of 169 

 miles, from England to Belgium, in 3J hours ; and the 

 Cody biplane, with which Mr. Cody won the British 

 Michelin Cup. The latter is fitted with a Green four- 

 cylinder engine. The Bl^riot machines shown in another 

 part of the exhibition are fitted with small skids at the 

 Tear in place of the single wheel present in last year's 

 machines. 



Many well-known types of engines are exhibited, those 

 most generally in evidence being the Gnome and the 

 Oreen. The Isaacson engine, made at the Boyne Engine 

 Works, Leeds, at first glance might be mistaken for a 

 Gnome. It has seven radi.nl air-cooled cylinders, which, 

 "however, do not revolve. The casing enclosing the crank 

 also contains a two to one reducing gear, so that the pro- 

 peller, which is coaxial 'with the crank shaft, rotates at 

 lialf its speed. The development of this engine will be 

 watched with interest. 



TBE GLANDS OF RUMINANTS. 



TN the issue of the Zoological Society's Proceedings for 

 December, 19 10, Mr. R. I. Pocock makes an important 

 addition to our knowledge of the specialised skin-glands 

 of ruminants. The value of this communication lies in the 

 fact that it is largely based on the examination and dissection 

 of animals from the society's menageries, whereas, with the 

 exception of the observations published years ago by Brian 

 Hodgson, much of our previous information appears to have 

 been gleaned from museum specimens, which are obviously 

 ill-suited for a study of this nature. The most common of 

 these glands occur near or between the base of the front 

 surfaces of the hoofs (pedal), on the carpus or " knee," 

 •where they form tufts in numerous antelopes, on the tarsus 

 and metatarsus of many members of the deer-tribe, on the 

 face below the eyes (preorbital), and in the groin (inguinal). 

 After a review of the structure of these glands, their 

 occurrence or absence in various genera, and their 

 taxonomic value, the author discusses, firstly, their func- 

 tion, and, secondly, their origin and evoluticwi. 



As regards function, Mr. Pocock is of opinion that the 

 limb-glands and hoof-glands are mainly for the purpose of 

 tainting the grass or ground through or on which the 



NO. 2 161, VOL. 86] 



animals have passed, or upon which they have lain, 

 thereby serving to indicate to the members of a specii-s 

 the wKereal>outs and the reposing-places of their fellow >, 

 the inguinal glands of sheep and many antelopes (orr<- 

 sponding practically, so far as their function is ' 

 to the tarsal and metatarsal glands of deer. Th<- 

 glands, on the other hand, appear to be > o .1 



considerable extent with the sexual function it is 



possible that they may likewise help in ...^ the 



members of a herd to the line taken by those in advance. 



Jn structure the preorbital glands range from a more or 

 less complexly invaginated sac to simple glandulation of 

 the surface of the skin ; and it appears that the knee-glands 

 of gazelles and the tarsal and metatarsal glands of deer 

 are of the latter simple type, the glandular area itsdf 

 being naked in a few deer. The glands in ''^" ■^"••n, on 

 the other hand, seem to be intimately con: h the 



milk-glands, their secretion in some instaii' i^ nn 



odour like that of sour-milk. The intcrdigital, or hoi.f, 

 glands take the form of invaginated sacs of varying 

 degrees of complexity, and appear to attain their fu; 

 development in the type of foot characterised by a ! 

 cleft between the toes in front and of a web connf 1 

 them behind, such as is found in deer, sheep, and 1: 

 antelopes. Such deeply cleft and highly glandular 

 must apparently be a source of weakness to bulky an': 

 which move rapidly on hard ground; and there accord i 1 : ^ , . 

 seems to be a tendency in such species to strengthen the 

 foot by obliterating the cleft, with the more or less com- 

 plete loss, not only of the interdigital, but of all limb 

 glands. The culmination of this takes place in cattle, 

 which lack glands both on the limbs and on the face. 



Apart from the consolidation of the foot and the loss of 

 the interdigital glands, the total absence of glands in the 

 members of the ox and buffalo group may, the author 

 suggests, be accounted for as follows : — 



" Large ruminants," he writes, " are much more easily 

 kept in view by members of their own species than sni.Tll 

 ones; or, if they live in thick bush, are more f -■'■ 

 followed by hearing, as they crash away in a state of i 

 through the vegetation." It is added, however, that r 

 and kindred subjects cannot be fully or definitely explained 

 in the present state of knowledge. R. L. 



T 



SOME NEW SOUTH AFRICAN MARIS E 

 ANIMALS.' 



HE volume referred to below contains a report on the 

 material collected during the investigations of the 

 Cape Government, carried out under the directjon of Dr. 

 Gilchrist. The larger part of the report is contributed by 

 Prof. R. Bergh in a paper on South .African opistho- 

 branchs (with fourteen plates). Prof. Bergh is able to 

 make a large addition to our knowledge of these animals, 

 since only five species have been previously recorded in 

 this region. He describes eight apparently new .Aplysias, 

 a Cape Philine, and other new tectibranchs. Many new 

 holohepatic nudibranchs were found, including a second 

 species of Kalinga. Several new cladohepatic nudibranchs 

 are also described, the most interesting of which is placed 

 in a new genus as Tritonidoxa capensis. The paper is 

 illustrated bv r.umerous valuable drawings of organs of 

 specific differential value, and there are two coloured 

 plates. 



In looking over Bergh 's anatomical contributions, one 

 concludes that he must have many valuable drawings of 

 complete svstems of organs, as, for example, of the 

 genitalia. There is no doubt that the publication of more 

 of such drawings would be warmly welcomed by students 

 of nudibranch anatomy. 



Reviewing the faunas of the coast west and east of the 

 Cape of Good Hope Peninsula, Bergh points out that 

 the former has a mwe northern character, with occasional 

 tropical nudibranchs, while the latter is more tropical. 



Dr. Gilchrist has an interesting contribution on three 

 new forms of hemichordata : a new species of Phoronis, 

 P. capensis, the behaviour and habits of which are 

 interestingly and fully described, and 'a form which differs 



1 " Marine Investigations in South Africa." Vol. v. Pp. 198. From 

 the Transactions of the South African Philosophical Society, vol. xviu 

 (Cape Town : Published by the Society, 1908.) 



