420 



NATURE 



ISept. 13, 1877 



During the discussion in the Frendi Academy the theory 

 suggested by M. Berigny tliat an echpse of the moon might have 

 an apprecialile efifect upon the temperature-conditions of our 

 atmosphere, namely, by cooUng the latter, does not seem to 

 have met with much encouragement. It would be more extra- 

 ordinary If such a phenomenon as a total eclipse of that luminary 

 were found to exercise no disturbing influence of any kind upon 

 the terrestrial atmosphere during the time of its occurrence. 



J. J. Wild 



The Development of Batrachians 



In reference to the article in Nature (vol. xv. p. 491) on the 

 development in certain instances of Batrachians without meta- 

 morphosis, Mr. B. G. Wilder writes to the American Naturalist 

 (vol. xi. No. 8, August, 1S77, p. 491) to point out that the 

 author of the article in Nature has overlooked Prof. Wyman's 

 observations on the development of Pifa americana, published 

 'vci^& American Jcrurnal of Science and Art for 1854 (ser. 2, 

 xvii. pp. 369-374). 



Wyman has there stated that the eggs of Pipa are transferred 

 by the male to the b.ick of the female, which presents " a uniform 

 surface throughout." " Their presence excites increased activity 

 in the skin, which thickens, and is gradually built up around 

 each egg, so as at length to inclose them in a well-defined 

 pouch." On pages 370 and 371 he figures and describes the 

 earlier embryos as having " three branchial appendages on each 

 side of the head." " In a later stage the external branchiae had 

 disappeared, but a small branchiil fissure was detected on each 

 side of the neck, and within this on each side a series of fringed 

 branchial arches." 



In endeavouring to obtain some confirmation of Prof. Wyman 's 

 observations, Mr. Wilder suggested an examination of certain 

 eggs of this singular Batrachian preserved in the Warren Ana- 

 tomical Museum of Harvard University. The examination was 

 made by Mr. C. S. Meriot, who reported as follows : — 



" I have examined two eggs from the back of the Pipa, and 

 found the embryos a little more advanced than that figured by 

 Prof. Wyman ; they are between 12 and 13 mm. in length. 

 The gills were partly absorbed, but a single slit wuh the gills 

 still projecting could be readily seen on each side at the back of 

 the head. I could not make a more detailed examination, as 

 the eggs were not well enough preserved." 



It would therefore appear that Dr. Peters' remark (which 

 was translated in the above-mentioned paper in Nature on 

 this subject) that "no one has defected branchin; in the embryo 

 of the Surinam toad " is not well founded. It would be very 

 desirable, however, to have further observations on this interest- 

 ing subject made, as likewise on the development of Hyhdes 

 martinicensis, which was the principal subject of the former 

 communication to Nature. P. L. S. 



Notes on the North East Australian Monolremata 



English naturalists seem to be "all abroad " on this subject, 

 judging from some remarks iu Nature, vol. xv. p. 257. 



P. L. S. states his conviction that Tachyglossus will be dis- 

 covered in the ranges of N. (Queensland vi-hen these have been 

 properly examined, being evidently quite unaware that both 

 Tachyglossus and Ornithorhynchus have been known to inhabit 

 the northern part of this colony for several years, and that a 

 discussion has been carried on for some months in the columns 

 of the Queenslamier, on the "Generation of the Echidna and 

 Platypus," between Dr. Bancroft and Mr. Befinett. I merely 

 allude to this subject to give English naturalists the latest dis- 

 coveries made by Dr. Bancroft in his researches into this more 

 than usual /nV/i-/)' subject. 



Dr. Bancroft dissected a female specimen and found a quantity 

 of milk in the stomach. He was unable to find any mammary 

 glands, and came to the conclusion that the mother Echidna fed 

 Its young by regurgitation. This theory was combated by Mr. 

 Bennett. 



On dissecting a second female Dr. Bancroft discovered the 

 mammary glands, but not like those of any other known 

 mammal, for the nipples were inverted, the cavities thus formed 

 being protected by stiff bristle-like hairs. 



The young Echidna h.is to thrust its bill into the cavity to 

 obtain its food. This is a curious adaptation to the wants of an 

 animal, for it is certain, from the curious formation of the head 



and rostrum, that it would be impossible for the young to suck a 

 nipple ; as it is the forcing in of the bill expresses the milk 

 which it is enabled to suck m when lying in the bottom of the 

 cavity. 



I secured a specimen of an adult female having a fine healthy 

 young one in the pouch, and preserved both. On opening the 

 stomach I noticed a quantity of a white substance which seemed 

 to be inclosed in a thin membr.ane. I did not know what this 

 was until I read Dr. Bancroft's letter on the su'iject, but unlike 

 him I arrived at a dilTerent solution of the puzzle. Instead of 

 the females .sucking themselves (the way in which Dr. Bancroft 

 accounts for the presence of milk in the stomach), I believe that, 

 after a certain time, when the spines begin to grow on the 

 young Echidna, the irritation causes the mother to take it out of 

 the pouch, and to feed it by regurgitation, until its spines are 

 sufficiently grown to protect it from its enemies. I was led to 

 this belief by discovering a nearly adult male with no sign of any 

 food in its stomach except milk. 



I was encouraged to dig this individual out of its stronghold, 

 by noticing several unusually large tracks going in and out of 

 the burrow. These, undoubtedly, were the footprints of the 

 female when she came to feed the young. The spines on this 

 specimen were not at all stifiT, especially at their bases, and 

 would have offered little or no protection against the attacks of a 

 native dog or eigle. This may seem a wild proposition, but I 

 have only adopted it after mature thought, and observing four 

 different females. 



We must adopt some explanation to account for so strange a 

 phenomenon, unless we jump the question by allowing that the 

 females of Tachyglossus suck themselves, a mosc unlikely pro- 

 ceeding on their part, and a solution to the difliculty as 

 unsatisfactory as it is improbable. We have only to guard 

 against chronicling false facts which seem to me to be the 

 greatest enemies which science has to contend with, and we are 

 not so apt to go wrong. Mistakes are often made, but invariably 

 meet with a correction, and should the above solution to a 

 difficulty which has taxed, and is still employing, some of our 

 wisest heads, prove wrong, I shall be only too glad to accept the 

 correction, thankful that my blunder has assisted in rightly 

 solving an interesting and vexed question. The blacks inform 

 me that the Echidna lays a white egg, and the Platypus a black 

 one, which are hatched in the abdominal pouch. 



I trust that some of your many scientific contributors will come 

 to our rescue in solving this point. W. E. A. 



The late discoveries by Goldie, D'Albertis, and MacFarlane, 

 have produced a number of forms (botanical) identical with 

 those obtaining in N. E. Queensland, thus further proving the 

 original fundamental unity of the two countries. The Australian 

 Dingo ought to be found in New Guinea as also our tiger cat. 



W. E. A. 



On Time 



I HAVE deferred my answer to the remarks of Mr. J. J. 

 Murphy (Nature, vol. xvi. p. 182) till now, in order to see if 

 my letter of June 14 would cause more discussion. But it 

 seems that my views are not deemed worthy of much con- 

 sideration in England ; I shall therefore say only a few words 

 in conclusion here, but hope to take up the question elsewhere. 



Mr. Murphy thus summarises a part of my letter: — "The 

 postulate that a velocity, e.g., that of the earth's rotation con- 

 tinues unchanged, is arbitrary, incapable of proof, and justified 

 only by pr.ictical convenience." I should wivh that he had 

 added, "and to be settled by definition." Mr. Murphy goes on 

 to say, " It seems to me, on the contrary, that the postulate is 

 not necessarily arbitr.iry but may be absolutely justified by fact." 

 I do not believe there is a great difference between " justi- 

 fying something by practical convenience" and "justifying it 

 absolutely by facts." Perhaps, in the opinion of Mr. Murphy, 

 the constancy of the velocity of the earth's rotation is proved by 

 the pendulum. But it is universally admitted that the pendulum 

 is controlled by the earth and not the earth by the pendulum. 



Mr. Murphy, in admitting that he sees no way of proving that 

 the force of gravitation continues unch.anged, acknowledges that 

 in natural philosophy many things are taken for granted which 

 call for closer consideration, and this was precisely my motive 

 for writing my letter. 



Though Mr. Murphy does not agree with me in all points I 

 am thankful for his remarks. \'. .\. Julius 



Breda, Holland, August 29 



