November i8, 1915] 



NATURE 



3-^/ 



that the theory of mimicry apiicarcil to offer the most 

 feasible interpretation of tlir coiiditions obtaining; in 

 'his genus. 



Geological Clunii^vs and the Distribution of Fish. 



Prof. A. Meek exhibited lantern slides of maps 

 ilkistrating Tertiary changes and their relation to 

 the distribution of hsh. He said that from geological 

 evidence it was known that during the Tertiary era 

 the northern hemisphere was the scene of important 

 changes affecting the sea and the land. A considera- 

 tion of the distribution of marine and fresh-water fish 

 bears out this evidence, indicates the refuge regions 

 of the Glacial epoch, and shows that the reaction of 

 changing conditions has during the era led to the 

 formation of many species {e.g. those of Acipenser) 

 and even of genera {eg. Caspiomyzon). The fish of 

 the Antarctic seas appear to be northern in origin, 

 but the fresh-water fish-fauna of the southern hemi- 

 sphere is characterised by the presence of primitive 

 types, which appear to have survived from the period 

 of Gondwanaland and the spread of the Glossopteris 

 flora. 



Regeneration of tJic Tail in the Lizard. 



Dr. C. Powell White gave an account of the re- 

 generation of the tail of Lacerta vivipara. Autotomy 

 of the tail takes place through the middle of a 

 vertebra ; there is no special autotomy site as in the 

 legs of crabs, but apparently any vertebra may be 

 involved. After autotoni\ llic wound is quickly 

 covered with new skin, bt m ath which is a mass of 

 spindle cells, originating in the connective-tissue, 

 which acts as a growing point to the new tail, and 

 from it the cartilage, fat, muscles, and vessels are 

 developed and differentiated. All the nerves are 

 derived from the last three pairs of nerve-roots in the 

 stump of the tail. The main trunks of the sym- 

 pathetic accompany the aorta some distance into the 

 regenerated tail and send branches to the different 

 blood-vessels. In the centre of the tail is an unseg- 

 mented tube of cartilage (perforated by blood-vessels 

 which pass to the interior) continuous with the body 

 and neural arch of the vertebra through which the 

 fracture took place. This cartilage surrounds an 

 epithelial tube continuous with the central canal of 

 the spinal cord. Regeneration may continue until the 

 regenerated tail is as long as the original one. 



llic ]'cn)iii<in)i Appoidix. 

 Dr. W. C. Mackenzie demonstrated a fine series of 

 specimens of the appendix vermiformis in Monotremes 

 and Marsupials. He drew attention to the fact that 

 Ornithorhvnchus has a caecum, whik' Echidna has a 

 true vermiform appendix, comparable macroscopically 

 and histologically to that of man, ape, and wombat, 

 the three mammals reirardcd hn having- a true vermi- 

 form appendix. In Pliasc-olonu s tlie appi'iidix has 

 reached a much more advanced degree of degenera- 

 tion than that of man, even to complete disappearance 

 by incorporation in the wall of the ileum (various 

 grades of this were shown), a condition suggestive of 

 the mode of further evolution of the appendix in man. 



An Explanation of Secondary Sex (lunaclcrs. 

 Mr. F. W. Ash suggested that niah- secondary 

 characters are characters of abandoned function sup- 

 pressed in the young in favour of more essential 

 growth (of organs still fullv functional), and in the adult 

 female because, with her, nutrilive surphis is more 

 directly diverted to tile purpixe'. of reprdchiction. Hence 

 such characters usually lind opijorlunitx for full ex- 

 pression in adult males. Secondary sex exaggerations 

 may significantlv parallel enlargements due to acci- 

 dental loss of function, e.g. the tusk of the male 



NO. 2403, VOL. 96] 



babirussa may be compared with occasional circular 

 overgrowth in the tusk of the hippopotamus. The 

 dependence of the development of the secondary 

 character on the presence of the active male gonad 

 ma\- perhaps be explained by reference to the pheno- 

 mena c\f periodicity. 



History of Comparative Anatomy. 

 Prof. F. J. Cole and Miss N. B. Eales presented 

 materials for a graphic history of comparative anatomy 

 based on an examination of 6304 papers on the 

 anatomy of animals published between 1543 and i860. 

 ITie graphs exhibited show that before the year 1650 

 onlv intermittent research was carried on, but m the 

 nex't fifty years there was considerable activity, cul- 

 minating at about 1683, and thereafter subsidmg. 

 This sudden revival was due almost exclusively to 

 Academia Naturae Curiosorum (founded 1652), the 

 Royal Society of London (1660), the French Academy 

 of Science (1666), and, to a less extent, the Collegium 

 Anatomicum of Amsterdam (1665). From 1700 to 

 1750 work was steadily maintained, and a second 

 revival began in 1750, gradually increasing to 1800, 

 and suddenly reaching a high maximum between 1835 

 and 1840, finally declining somewhat to i860, where 

 the investigation ceases. The second revival was 

 initiated by France, followed closely by Germany, and 

 at some distance by England, but the last country 

 reached her maximum first, then Germany, and finally 

 France. , Holland and Denmark took a distinct part 

 in the seventeenth-centurv r( vi\ah and Italy was un- 

 doubtedly concerned in initialing the similar move- 

 ment in the nineteenth century. The seventeenth- 

 century revival related chiefly to mammals, but con- 

 cerned to a less extent birds, fishes, and arthroix)ds, 

 and to a slight extent reptiles and molluscs. In the 

 nineteenth-century revival, mammals, arthropods, 

 fishes, and organography play the leading part, fol- 

 lowed by birds, molluscs, and reptiles. 



Dr. J. Stuart Thomson gave an account of the 

 morphologv of the telencephalon of Spinax as a type 

 of Elasmobranch fore-brain, and detailed the various 

 grey masses and fibre-tracts which he had recognised. 

 He' has not obtained any satisfactory evidence of the 

 existence of a corpus callosum. 



Dr. A. E. Cameron described the insect community 

 of a local environmental complex. A soil-insect census 

 of two different grasslands in the association, differ- 

 ing in their soil-types and vegetational covering, 

 showed that in any given locality the soil-insect fauna 

 of grassland is not likelv Ki var\ to anv great extent. 

 In the absence of the ilhiNtralion. ihesetwo com- 

 munications cannot be adequafelx Minimarised. 



On the Thursday afternoon the ni.mbers of the 

 Section were received hv Prof, and Mrs. Hickson in 

 the Zoological Lahoraiori.s \vh. r.' there was an 

 interesting and extensive exliihii ot specimens by 

 members of the staff and bv visiting zoologists. 



J. H. Ash WORTH. 



EDUCATION AT THE BRITISH 



ASSOCIATION. 



AS women are |)la\ini4 an ever-inrrea>ni,i4 part _ in 

 the national work of education, it wa- an emin- 

 ently reasonable departure from preicdent for the 

 council of the Association to i lei t Mr^. Sidgwick to 

 the presidency of Section L. The full text of her 

 address has already appeared in Nature, and need 

 not, therefore, detain us here, except in so far as i^t 

 gave an opportunitv to Lord Hr\ce to dot the "i's" 

 and cross the ■■t'>""of wiiat was, in fart, an extremely 

 sane pronouncement. Those who heard him will not 



