1897. SOME NEW BOOKS. 



129 



-the whole. Let us take the asexual reproduction by means of 

 zoospores in V. repens and V. clavata. The relations to this process 

 of the following factors are considered in order, namely, (i) nutrition, 

 ■(2) moisture, (3) light, (4) temperature, (5) chemical nature of the 

 environment, (6) oxygen, and (7) currents of water. In the case of 

 nutrition it was found that starvation, by growing in the dark, 

 thereby stopping formation of carbohydrate, after a time prevented 

 zoospore-formation, though growth still continued. Similarly, plants 

 cultivated for a month in distilled water, though exposed to the light, 

 grew slowly, but could not be induced to form zoospores. In the 

 second case the alga was grown for some days in damp air. Under 

 such conditions there arise from the threads which lie on the sub- 

 stratum, numerous branches, which, when surrounded by water, 

 produce zoosporangia at their ends. In damp air the sporangia were 

 never formed. The addition of water acts as a stimulus, and the 

 transition must accordingly be sudden ; if gradual there is no result. 

 By exclusion of light, formation of zoospores was induced often after 

 twenty-four hours only. Care must of course be taken that the exclu- 

 sion of light is not of long enough duration to cause starvation. 

 Experiments with different coloured solutions indicate that shutting 

 ■off the yellow-red rays is especially favorable to zoospore-formation. 

 Klebs has previously shown that the process in question ceases below 

 3° C. and above 26° C. He also finds that temperatures between 10° 

 'C. and 20° C. are equally favourable to zoospore-formation, so that 

 within these limits temperature ceases to be a factor in any given 

 experiment. Increase of the amount of oxygen in the water in which 

 the plant is growing does not lead to production of zoospores. By 

 transposing individuals from streaming into stagnant water, rapid 

 formation of zoospores was induced; probably as a result of a diminu- 

 tion of the amount of dissolved oxygen. These few remarks give but 

 little idea of the numerous observations occupying 80 pages of the 

 text. For details, and for an account of the remainder, we refer our 

 readers to the book itself, to which physiologists in general, and serious 

 workers at Algae and Fungi in particular, will, we feel assured, give a 

 liearty welcome. 



Names at the Zoo, 



List of the Vertebrated Animals now or lately Living in the Gardens 

 OF THE Zoological Society of London. Ninth edition (by P. L. Sclater). 

 8vo. Pp. xvi., 724, with 70 woodcuts. London : Printed for the Society, 1896. 

 Price 4s. 6d. 



The last edition of this valuable list appeared no less than thirteen 

 years ago, so that the handsome new volume contains the records of 

 twelve years (1883-95), arranged, as usual, in systematic order. The 

 names of species recorded in the previous lists are also added, with 

 references, so that the present work is practically an index to all the 

 species of vertebrated animals received alive by the Zoological Society 

 of London during the past thirty-four years. As regards the name's 

 used, Dr. Sclater has endeavoured to make as few changes as 

 possible, "not being one of those advocates of priority who seek to 

 carry out that useful principle without reference to grammar or 

 common sense." Nevertheless, so far as the new series of British 

 Museum Catalogues has advanced, he has adopted the various 

 "revisions" of nomenclature without any question. This does not 

 seem to us quite consistent — merely to use " revised terms " where 

 they are ready to hand and need no seeking — but it at any rate 

 .displays great good sense to follow implicitly some standard work of 



