4o 



NA TURE 



[November 9, 1905 



the prospects of future development of the industry in 

 South Africa, and of its heing successfully developed in 

 other countries. The reports of the committees on grants, 

 which were also taken on this day, did not offer any 

 special points of general interest. 



The greater part of the sitting on August iX was devoted 

 to a paper on the origin of mammals, by Prof. Broom, in 

 which the author had occasion to make extended reference 

 to his work on the Triassic reptiles of South Africa in 

 support of his views of a reptilian origin for the mam- 

 malian group. The author gave reasons for believing that 

 in early Permian times a cotylosaurian reptile, owing to 

 its frequenting marshy ground, took to walking with its 

 body well supported off the ground. This habit gave rise 

 to the forward direction of the ilium, and to the pubis 

 and ischium being turned backwards, as also to the great 

 development of the precoracoid. No member of this first 

 stage in the mammalian line was at present known, but 

 Pareiasaurus was apparently a considerably modified off- 

 shoot from it. 



The next si.igr in the development arose by the marsh 

 animals finding that the new modification of the limbs 

 was specially suitable for progression on land. The new 

 type of land animal was better equipped than the normal 

 ' reptile, and took to predatory habits and became an active 

 carnivorous animal. These early carnivorous types form 

 the order of Therocephalians, of which about twenty genera 

 are known. Between tin- Upper Permian and the Upper 

 Triassic times the Therocephalians gave rise to the much 

 improved Theriodonts or Cynodonts. These Theriodonts 

 are almost mammals in every detail of structure, the only 

 essential difference being that the lower jaw has still a 

 small articular element, which hinges on a small quadrate 

 bone. The change from the Theriodont to the mammal 

 was probably brought about by a slight change of habit 

 necessitating some antero-posterior movement of the jaw, 

 the small quadrate bone becoming first a plate of bone 

 and then a plate of cartilage — the inter-articular cartilage, 

 the dentary taking the place of the articular. Neither the 

 auditory ossicles nor the tympanic have ever had anything 

 10 do with the articulation. The mammalian malleus was 

 held to be the reptilian extra-stapedial and the mammalian 

 incus the supra-stapedial. The connection between 

 Meckel's cartilage and (he malleus, which is hyomandi- 

 bular, was held to be similar to that between the extra- 

 stapedial and the mandibular cartilage in the crocodile. 

 The mammalian tympanic w-as considered to be the homo- 

 logue of the distinct tympanic bone of Anomodonts .mil 

 Theriodonts. The paper gave rise to considerable dis- 

 1 11-sion, in which Prof. W. B. Scott of Princeton, the 

 president, and others took part, and was followed by a 

 communication from Dr. W. F. Purcell on some earl) 

 stages in the development of Peripatus, in which the writer 

 maintained that an examination of the segmentation stages 

 of the ovum of Peripatus balfouri preserved in formalin 

 shows that the endodermal cells are oval or spherical 

 bodies with well defined convex or flattened contours, but 

 without any anastomosing branches connecting the cells 

 with one another or with the ectoderm. The embryo in 

 the segmentation stages is therefore not a syncytium, as 

 maintained by Mr. A. Sedgwick. The remainder of the 

 session was devoted to an important paper on the habits 

 and peculiarities of South African ticks, by Mr. C. P. 

 Lounsbury, which the sectional committee resolved to 

 print in extenso in the Proceedings of the association, 

 whilst ,eit, on details in the structure of the buccal 

 apparatus of a tick (Haemaphysalis punctata) were 

 elucidated in a concluding joint paper by Drs. Nuttall, 

 Smedley, and Cooper. 



The firSl • 1 . 1 \ el the pr, ,c eec 1 i n g - ,,| Johannesburg 



(Tuesday, August 29) was opened by Prof. Herdman, 

 F.R.S., who gave an account, illustrated with lantern 

 views, of his well known investigations on the pearl- 

 oyster beds ol Ceylon. This was followed by an interest- 

 ing communication on Cephalodiscus by Dr. S. F. 

 Harmer, F.R.S., in which the author gave a preliminary 

 account of the new species discovered in African seas l>\ 

 Dr. Gilchrist. The session was concluded with a demon- 

 stration of ankylostoma preparations by Mr. A.'E. Shipley 

 I R S. 

 The programme for Wednesday, August 30, was opened 

 NO. l88o, VOL. J $] 



by Prof. E. B. Poulton, F.R.S., who gave a lecture, illus- 

 trated with lantern slides, on mimicry in South African 

 insects. This was followed by a paper by Mr. W. L. 

 Sclater, director of the South African Museum, on the 

 migration of birds in the southern hemisphere. For the 

 purposes of the paper the author took the list of birds 

 contained in the recently published volumes of the " Fauna 

 of South Africa," written by the late Dr. Stark and him- 

 self, together with those of the fourth volume, shortly to 

 be issued. The number of species described in the four 

 volumes was 814, which the author divided into five 

 categories, as follows: — residents, 631; northern migrants, 

 76; African migrants, 21; partial migrants, 50; and island 

 breeders, 36. Mr. Sclater stated that he considered it 

 would be most unwise to evolve any theories on migration 

 in South Africa at present, owing to the dearth of observ- 

 ations hitherto recorded. He was, however, in hopes of 

 making some advance by the distribution of schedules 

 among the lighthouse keepers along the coast, teachers in 

 the schools all over the country, and any others who would 

 undertake to make the observations, for the purpose of 

 recording, day by day and month by month, the appearance 

 of different species of birds. 



Mr. C. B. Simpson, the Transvaal Government en.omo- 

 logist, then read a paper on locust destruction in the 

 Transvaal during the season 1904-5, in the course of which 

 the writer gave an outline of the history of the locust pest 

 in other countries, and then proceeded to describe the 

 locust invasions in South Africa, due to two species, 

 Acridium purpuriferum (the purple locust) and Pachytelus 

 sulcicollis (the brown locust). Although both species were 

 shown to have many natural enemies, yet every natural 

 method of decimation was found to be insufficient. There- 

 fore, in order to save the farmers' crops, recourse had to 

 be had to artificial means. Amongst the methods adopted 

 were beating by hand, tramping with stock, crushing with 

 rollers, burning grass, driving into trenches, the use of 

 locust screens, and spraying. The screens were described 

 in detail with the help of the lantern, the author stating 

 that twenty miles of them were distributed throughout 

 the Transvaal for the use of farmers. Spraying was, how- 

 ever, tin most efficient means for the destruction of locusts. 

 I be spray used was arsenate of soda, and it was given 

 to the farmers free, wdiile the screens and spray-pumps 

 were lent without charge. The results of the campaign 

 in the previous year had been most gratifying. It was of 

 course slated that the Transvaal, still less South Africa, 

 could not expect to eradicate tlie pest completely mi account 

 of the vast area of unoccupied country ; but the author's 

 department did hope to place in the hands of the farmers 

 .1 means whereby by combined action they could kill 

 the insects and protect their crops. If they could do this 

 they would consider that success had been achieved. With 

 the purple locust the author believed they had proved 

 that the farmers could do this, but with the brown locust 

 they bad not yet had sufficient experience to be able to 

 tell whether they could prevent injury or not. I he con- 

 cluding paper of the session, by Dr. H. Lyster Jameson, 

 was entitled " On Some South African Land Planarians," 

 and dealt with certain points in their anatomy. 



1 he coin hiding meeting of the section was held on 

 Friday, September 1, on which day Prof. W. B. Scott, in 

 an opening paper on convergent evolution as illustrated 

 by the Litopterna, maintained that while convergent evolu- 

 tion was admitted by most naturalists to be a frequent 

 and important phenomenon, there was a great difference 

 of opinion as to how nearlv identical the results of such 

 a mode of development might be. So far as the Litopterna 

 were concerned, there were striking resemblances to certain 

 Perissodactyls in teeth, skull, and skeleton, but the differ- 

 ences were many and fundamental. It did not appear at 

 all likely that so complex a structure as a mammalian 

 skeleton was ever produced in identical terms by two 

 independent sines. 



In the course of the succeeding paper, cm a neuro- 

 svnevtial theory of development, Dr. W. II. Gask HI, 

 F.R.S., referred to his theory of the origin of vertebrates, 

 and pointed out that it was leased upon the paramount 

 importance of the central nervous system as the chief factor 

 in the upward progress of the animal kingdom. Every 

 line of investigation pointed to the conclusion that the 



