Nov. 23, 1888.] 



SCIENTIFIC NEWS. 



533 



had been bitten there were raised spots whiter than the 

 skin and occasioning a very intense and unpleasant 

 irritation. 



" In another journey, and under similar conditions, I 

 had to suffer from the same affection, which redoubled in 

 intensity at night and completely prevented sleep. 



" The most interesting fact is that in this desert, just 

 before the passage of our caravan, the Tsetse had put to 

 rout an army. The Massai, to the north of Zanzibar, 

 constitute a numerous nomadic pastoral tribe extremely 

 dreaded on account of their warlike disposition. This 

 tribe, in the intention of attacking Mrogaro, had encamped 

 in the desert plain which has just been mentioned, 

 having with them a herd of 300 oxen. The people of 

 the country were much alarmed, when they suddenly 

 learnt that the Massai had retired with precipitation. 

 The Tsetse had interfered, and the destruction of their 

 oxen had compelled the Massai to withdraw. 



" I have just read that Dr. Laboulbene attributes the 

 effects of the bite of this fly to its settling upon putrid 

 carcases. I doubt whether the experiments which he is 

 about to make will confirm this hypothesis. In any 

 case the difficulty is to explain why the bite is deadly to 

 the ox and not deadly to man." 



The Horses of the Pampas. — Sen. J. Solveyra for- 

 wards to La Nature some interesting information con- 

 cerning the horses of the Pampas of La Plata. In that 

 region there are three millions of horses of Arab blood, 

 since their progenitors were originally imported from 

 Andalusia. Their peculiar beauty, strength, and stay- 

 ing power are well known, and many of them have been 

 lately purchased for the French army. Mounted upon 

 such horses, good riders have been known to travel 200 

 kilometres (=120 miles) in twenty-four hours. Races 

 have been instituted at Ayacucho to test the endurance 

 of these horses. The horses were to travel for ten 

 hours ; the riders might at pleasure stop, dismount, and 

 go at a walk, a trot, or a gallop. The winner was 

 Recluta, belonging to Sen. Bandrix. This horse 

 travelled in ten hours 143 kilometres, i.e., 88 miles. 



A New Weed. — A novel pest has appeared in some 

 districts of the State of New York. It is a species of 

 house-leek, known to botanists as Hieracium pracaltum, 

 unfavourably known in Europe, and apparently of recent 

 introduction in America. It has there become more 

 rampant, and on account of the annoyance it occasions, 

 it has received the name of the " King Devil." When 

 it once appears in a field it covers the entire surface 

 with its leaves, so that nothing else can grow. 



The Diet of the Pheasant. — A correspondent of the 

 Field gives an interesting account of the animal diet of 

 the pheasant. Upwards of 1,200 wire-worms have been 

 counted in the crop of a single pheasant, and in another 

 there were found 440 larvae of the daddy-long-legs 

 (Tipula oleracea), a most destructive insect. From 

 another three young vipers have been obtained. Hence 

 the pheasant, quite independently of its value as food, 

 merits public goodwill and protection. 



Mischievous Industry. — Mr. Walter Hough, in a letter 

 to Science, mentions that he has caught ants in the very 

 act of transferring scale insects {Coccidce) from one plant 

 to another. 



THE TEETH OF WHALES. 



Part I. 



T^HERE are very few families of tooth bearing animals 

 J- in which the dentition varies so greatly as in the 

 whales. Generally speaking, the dental formula, to use 

 the technical expression, is very much the same in all 

 the members of a given group. There may perhaps be 

 variation in individual species ; that is not unusual. But 

 it is seldom noticeable in any great degree. And so 

 true is this as a general rule that in many cases the 

 dental structure is considered, and justly considered, as 

 one of the strongest and most unfailing of family 

 characteristics. 



But in the order of the Cetaceans, which comprises the 

 whales and their allies, many ordinary rules are partially 

 or wholly abrogated ; and this among them. And 

 there are scarcely any two species whose teeth are of 

 similar character. A whale may have teeth — and almost 

 any number of teeth — or it may have none. If it possess 

 them, they are quite unlike the teeth of other mammals. 

 There is no distinction between molars, canines, and 

 incisors, for all are alike in form and in size. A greater 

 number may be present upon one side of the mouth 

 than upon the other; and, more remarkable, perhaps, 

 still, different individuals of the same species may very 

 possibly exhibit quite a different tooth-armature. Thus 

 it is quite evident that, as far as these animals are con- 

 cerned, we must not look for family characteristics in 

 the teeth ; and the only respect, indeed, in which we can 

 employ those organs for purposes of classification is by 

 dividing all living cetaceans into two great groups, or 

 sub-families, the one comprising those species which 

 possess teeth, and the other those which do not. 



I purposely employ the adjective " living " for the good 

 and sufficient reason that in earlier days of the world's 

 history a group of cetaceans existed whose teeth pre- 

 sented very well-marked characteristics, the molars 

 being perfectly distinct from the incisors, and the incisors 

 from the canines. Such were the Zeuglodons, the 

 Phocodons, and the Squalodons, the former of which 

 seem to have dwelt in New World waters, their fossil 

 remains being not uncommonly found in the Eocene and 

 Miocene strata of Northern America, while the members 

 of the two latter genera had a wider range, and have 

 left their relics behind them in most European countries 

 as well as in Australia and the United States. All these, 

 however, have long died out, in company with most of 

 the giants which were on the earth in those days, and our 

 latter-day cetaceans are represented by two groups only, 

 the one of the Denticetes, or toothed whales, and the 

 other of the Mysticetes, or those whose mouths are 

 furnished with whalebone. 



Much discussion has arisen over this most curious 

 substance, its nature, affinities, and uses. It is scarcely 

 necessary to state that its title is a most misleading one, 

 and that it has nothing to do with true whale's bone at 

 all ; but many have been puzzled by the question as to 

 whether it is, or is not, a modification of the teeth. Not 

 that it exercises any of the ordinary functions of those 

 organs. It is obviously useless for purposes of mastica- 

 tion, and, although it certainly assists in the capture of 

 prey, it does so in a manner very different to that in 

 which the teeth of any other animal are employed. And 

 the material of which it is composed is undoubtedly 

 quite distinct from either bone, dentine, ivory, or enamel, 

 the only four substances which enter into the qompos}- 



