March, igo6.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



391 



be cited as instances where the single cascum is of large size, 

 this being especially the case in the former, where it is of 

 enormous dimensions ; in human beings, on the other hand, 

 the caecum is rudimentary, and best known in connection 

 with "appendicitis." 



The existence of paired cteca was previously known in a 

 few armadillos and ant-eaters, but Dr. Mitchell has now shown 

 that they are quite common in these groups, while he has 

 also recorded their occurrence in the hyrax and the manati. 

 With the aid of these instances of paired c;Eca, coupled with 

 the frequent existence of a rudiment of its missing fellow 

 when only one is functional, the author has been enabled to 

 demonstrate conclusively that these double organs in birds 

 correspond in relations with their normally single representa- 

 tive in mammals. 



Teeth of Early Carnivora. 



Much difference of opinion has obtained among naturalists 

 with regard to the aflinities of certain extinct carnivorous 

 mammals from the Tertiary ftrata of South America, some 

 authorities regarding them as more akin to the predaceous 

 marsupials, while by others their relationships are believed to 

 be closer with the primitive European and North American 

 Carnivora known as creodonts. This opens up the wider 

 question as to the existence of a direct relationship between 

 creodonts and marsupials. On this difficult question con- 

 siderable light has been thrown by investigations into the 

 structure of the enamel of the teeth of the two groups, the 

 results of which were recently communicated by Mr. Tomes 

 to the Zoological Society. According to the author, marsupial 

 teeth show in the structure of their enamel a well-marked 

 peculiarity, namely, the free penetration of the enamel by 

 tubes continuous with those of the dentine ; while recent Car- 

 nivora, the descendants, more or less direct, of the creodonts. 

 also present a disposition of the prisms of their enamel some- 

 what unusual amongst mammals. Teeth of Hycriuniun and 

 other extinct genera were examined, and in none of them were 

 marsupial characters observed. On the contrary, in most 

 cases characteristic carnivorous patterns were found, so that 

 in Oligocece and Eocene times the enamel of the ancestral 

 Carnivora had already attained the full specialisation charac- 

 teristic of the modern group. 



Weights of Whales and Dinosaurs. 



With characteristic boldness and originality American in- 

 vestigators have recently been making the attempt to estimate 

 the approximate " live- weights " of the huge dinosaurian reptiles 

 of the Oolites, such as Diplodocus and Droiitosaiinis. Although 

 at first sight the attempt might appear almost hopeless, their 

 method of going to work has been so thorough and well 

 thought out that there appears to be considerable probability 

 of the estimates at which they have arrived presenting a fair 

 approximation to the reality. The plan adopted was to 

 make a modt 1 of the entire reptile, as deduced from a care- 

 ful study of the skeleton, on a scale of one-sixteenth the 

 natural size. The cubic contents of such a model multiplied 

 by the cube of 16 would indicate the probable amount of 

 water displaced by the reptile when in the flesh. To arrive 

 at this result, one of the miniature models of Broiilosiiunis (the 

 length of whose skeleton is 66.5 feet) was cut into six pieces of 

 convenient size for purposes of manipulation ; and the equi- 

 valent water-displacement of each of these fragments deter- 

 mined with great accuracy in the laboratory. Erom this the 

 water-displacement of a model of the natural size was calcu- 

 lated by means of the above-mentioned formula, which gave 

 as a result the displacement of 34} tons by the entire auimal. 

 Since, however, Broiitosanrus is believed to have walked along 

 the bottom of the ancient lakes in search of food to depths 

 which would cause its whole body to have been submerged, it 

 is probable that the reptile in life was slightly heavier than 

 water, and to allow for this an addition of about ten per cent. 

 was made to the calculated weight, thus bringing the final 

 estimate to a total of 3.S tons. Vast as is this weight, it is, 

 however, only about two-thirds of the estimated weight of the 

 heaviest whales, which is presumed to be not less than 60 tons. 

 Further information with regard to tins latter estimate appears 

 desirable, and it would be interesting to know which of the 

 larger species is really the heaviest. The C.reenland right 

 whale would, from its great bulk, of course weigh well ; but as 

 the maximum length of this species was estimated by Sir 

 William Flower at from 45 to 50 feet, while the male sperm- 



whale is known to measure from 55 to 60 feet, it is possible that 

 the latter monster would scale heavier than the former. On 

 the other hand, despite its length of from So to 85 feet, the 

 huge Sibbald's rorqual, on account of its '• clipper-built " 

 form, would probably weigh less than either the Greenland 

 whale or the sperm-whale. Any estimates of the weights of 

 whales based on trustworthy data would be of much interest. 

 It may be added that the weight of the African elephant 

 " Jumbo " was only 5i tons, and although some individuals of 

 the species may perhaps be somewhat heavier, it is clear that 

 elephants are not in the running in comparison with the 

 American estimate of the weights of dinosaurs. 



The Flight of Flying-Fishes. 



In the course of a memoir on fossil flying- fishes, published 

 in the Year- Book of the Austrian Geological Survey, Dr. O. 

 .\he\ reviews the much-discussed question as to whether the 

 existing representatives of such fishes — which belong to two 

 distinct groups, the flying-herrings, or true flying-fishes, and 

 the flying-gurnards — really use their " wings " after the manner 

 of bats, or whether such wings merely serve the same purpose 

 as the flying-membrane or parachute of the flying-squirrels. 

 In the case of both flying-herrings and flying-gurnards, the 

 author denies that the wings are ever used as instruments of 

 active flight. As regards the former. Dr. Abel's opinion agrees 

 with that of the majority of competent observers. In regard 

 to the flying-gurnards it has, however, been stated in the 

 " Cambridge Natural History " that these fishes differ from the 

 members of the former group in that the wings are moved 

 rapidly during the courre through the air, thus producing a 

 mode of flight recalling that of many grasshoppers. This 

 assertion is, however, controverted by Dr. .\bel, who urges 

 that such movements as take place in the wings of fljing- 

 gurnards are similar in their nature to the vibrations which 

 are admitted to occur in those of the flying-herrings or true 

 flying-fishes. The author's statement of the whole case is 

 summarised as follows : — 



" It may be taken as certain that the initial impetus by means 

 of which flying-fishes of both kinds launch themselves is due 

 to powerful screw-like movements of the tail-fin. The wings 

 are in no sense propelling organs, but act simply as parachutes." 



In striking contrast to this conclusion is one arrived at by 

 an author in the January number of the Anuah and Ma!;a:inc 

 of yatnral History. According to this, the aeroplane theory, 

 as the above maybe called, is an absolute mechanical impossi- 

 bility, and the flight of flying-fishes is due to incessant and ex- 

 tremely rapid movements of their wing-like fins. 



A Male Fish-Nurse. 



It has long been known that the males of the strange-looking 

 pipe-fishes take charge of the eggs as soon as they leave the 

 bodies of the female parents, and nurse them in a special 

 pouch on the under side of their own bodies; but it appears 

 to have been reserved for an American naturalist to observe 

 the actual manner in which the transfer of the eggs takes 

 place. I'rom his account, it seems that the male and female 

 fishes entwine their bodies in the form of a double letter S, 

 and that in this position the eggs are passed from the mother 

 to the pouch of the male. As might have been expected, all 

 the eggs are not transferred at once. .-Xfter the first transfer- 

 ence all the eggs of this batch are in the upper part of the 

 pouch, where no more can be received until these are shaken 

 down into the lower end. "To bring this about," writes the 

 narrator, " the male performs some very curious movements. 

 He stands nearly vertically, and, resting' his caudal fin and a 

 small part of the tail on the floor of the aquarium, bends back- 

 ward and forward, -and twists his body spirally from above 

 downward. This is repeated until the eggs have been moved 

 into the posterior end of the pouch." These processes are 

 repeated until the pouch is filled. In about ten days the young 

 pipe-fishes are hatched. 



Papers R.ead. 



At the meeting of the Zoological Society held on January 16, 

 Mr. O. Thomas exhibited skulls of a "forest-pig from the 

 Cameroons district, which he referred to a new species, under 

 the name of Ilylochirnts r'uiiatcy. Mr. W. S. Fox read a paper 

 on bones of the lynx from a Derbyshire cave; Mr. C. S. Tomes 

 discussed the structure of the enamel of the teeth in Carnivora 

 and marsupials ; Mr. F. E. Reddard described the results of 

 investigations into the anatomy of snakes ; and Dr. J. Koux con- 

 tributed a list of the species of a particular group of toads. 



