igi 



NATURE 



[August 12, 1909 



and it may be some time before this can be stated, 

 owing to the difficulty of capturing the slippery and 

 swift-moving adults. It will be necessary to have 

 these for comparison with the leptocephali (e.g. to 

 count the vertebra;). From the small numbers of 

 these leptocephali c.Tptured, it is practically certain 

 that their breeding-places or " nurseries " are con- 

 siderably to the south of the Bay of Biscay. 



Lepto'ccphahis hyoproro'ides is particularly interest- 

 ing, because it is the only species which it has been 

 possible to trace back to the not fully-grown pre- 

 leptocephalus stage, which, it is significant to ob- 

 serve, is also pelagic, like the later stages. 



Much praise is due to those concerned in the 

 production of the three beautiful plates of photographs 

 which illustrate these two pajjers. One plate (in 

 No. 3) shows seven stages (typical size) in the meta- 

 morphosis of the common eel. These figures are a 

 great improvement on the photographs of the same 

 series of stages published in Dr. .Schmidt's original 

 treatise ; they are larger, and were taken from speci- 

 mens in a much better state of preservation, so that 

 they display the characters of the larvae, especially 

 the glassy transparency, more faithfully. The same 

 remark applies to the plates illustrating No. 6. One 

 of these shows seven stages in the growth of the 



L€plS£J/hiilns tattts. Slightly le;s than three t 



pre-leptocephalus into the leptocephalus of " hyopro- 

 roides." 



Dr. A. C. Johansep, 7/1 No. 5, makes a vers' im- 

 portant original corx.riC>utica to the much vexed 

 question, " Is the plaice indigenous to the true 

 Baltic?" For a long time, neither eggs, pelagic 

 larvae, nor early bottom stages of the plaice could 

 be found in the true Baltic, and Dr. Petersen, the 

 chief Danish scientific expert on sea fisheries, con- 

 siidered that the large stock of this fish in these 

 waters must be entirely derived by immigration from 

 the Belts and southern Kattegat. He thought that 

 they must begin to immigrate when about one year 

 old. As time went on, however, the capture of large 

 numbers of eggs in the cold saline bottom water of 

 the Baltic, and of occasional pelagic larvae and bottom 

 fry, seemed to indicate that this extreme view might 

 require modification. It seemed unlikely, hov.ever, 

 that the eggs could de.-elop in the cold water at that 

 depth, and the fact t'nat the number of pelagic fry 

 obtained were extremely few in comparison with the 

 numbers of eggs and adults lent support to thi.-- 

 view. But is was not impossible that the stock of 

 plaice was partly, if not mainly, indigenous, being 

 an " accumulated stock " grown up slowly by means 

 of small additions from year to year. This problem 

 NO. 2076, VOL. Si] 



had been the subject of continual investigation and 

 discussion by German and Danish investigators under 

 the international scheme, with, so far, inconclusive 

 results. It seemed even probable that a third alterna- 

 tive might be the right explanation, viz. that the 

 fry had not been looked for in the right places with 

 the proper appliances. This seems to have been the 

 case. Dr. Johansen, in the present paper, records the 

 capture in the true Baltic of large quantities of year- 

 ling plaice " for the first time in such numbers as 

 to compete with each of the older annual series." 

 He also found that pelagic fry of this species were 

 plentiful everywhere in the water between Falster and 

 Bornholm. Other convincing evidence of the plaice 

 being indigenous to the true Baltic is also brought 

 forward, it being shown that the average size of plaice 

 of a given age and the average size at first maturitv 

 are much smaller in the Baltic than in the Belts and 

 southern Kattegat. This could hardly be the case if 

 any considerable immigration from the latter regions 

 took place. More light on this question may reason- 

 ably be expected from marking experiments in the 

 future. The few experiments of this kind which have 

 so far been made in this region have not yielded con- 

 clusive results. 



In No. I, Dr. C. G. Joh. Petersen gives the results 



of an exhaustive 

 study of the di- 

 agnostic charac- 

 ters of Arno- 

 glossus, Zeugop- 

 terus, and Solea 

 in the larval and 

 post-larval stages. 

 These results 



(which need not 

 be detailed here) 

 are quite new. 

 The author also 

 discusses in a 

 critical manner all 

 previous observa- 

 tions in regard to 

 these species and 

 stages. Dr. Peter- 

 mes nitur.ii size. sen is the greatest 



living authority 

 on the later development of the Pleuronectida, and 

 this paper and his other papers dealing with the sub-- 

 ject are of standard importance, and indispensable to 

 the investigator. 



THE POSITION OF SCIENCE TE.iCIIING IN 

 PUBLIC SCHOOLS. 



T^HE Board of Education has issued as an " Educa- 

 ^ tional Pamphlet " a report on science teaching 

 in public schools. The mater'al for this report, made 

 at the instance of the Association of Public School 

 Science Masters, has been collected and edited by Mr. 

 O. H. Latter, of Charterhouse, and the pamphlet is 

 both instructive and amusing. The ground covered 

 by the report is to some extent the same as in another 

 report recently made by a committee of the British 

 ^Association on the sequenca of science studies in 

 secondary schools ; but a corrparison of the two lists 

 of questions sent out will show that Mr. Latter's in- 

 vestigation deals more particularly with equipment and 

 finance. On the other hand, the field of inquiry was 

 restricted to the class-- of school represented on the 

 Association. 



Of the seventy-one schools to which the circular was 



