58 



SCIENCE 



[N. S. Vol. XXXII. No. 810 



point, but I think the statement I have just 

 made for plant diseases as a whole is quite 

 true. The late Marshall Ward came the near- 

 est perhaps to being such a man, and yet to 

 the writer Dr. Duggar's book shows a better 

 grasp of the whole subject and is more inter- 

 esting than either one of the books which 

 Marshall Ward published. All criticisms of 

 this sort would have been forestalled by the 

 use of a slightly different title. 



In conclusion the writer feels like recom- 

 mending this book heartily and hopes that it 

 may have so prompt and wide a circulation in 

 this country that a new edition may be called 

 for soon. Meanwhile for the digestion of the 

 physiological critics, it may be suggested that 

 it is a good deal easier to point out the defects 

 in a good book than it is to write a better one. 

 Undoubtedly the ideal plant pathology would 

 be one in which a just balance is kept between 

 the activities of the parasite on the one hand 

 and the reactions of the host plant on the 

 other, and when we know enough about these 

 two subjects, then it will be very easy to write 

 such a book, but the time is not yet. Mean- 

 while, let us take what we can get and be 

 thankful, particularly when it is as good as 

 the volume in question. 



Eewin F. Smith 



U. S. Depaetment of Agkiculture 



ZOOLOGY OF THE INDIAN OCEAN 



The Percy Sladen Trust Expedition to the 

 Indian Ocean in 1905. Eeports 22-33. 

 (Trans. Linnean Soc. London, 2d Ser., 

 Zoology. Vol. XIII., Pts. 1 and 2, October, 

 1909, February, 1910.) 



The important collections brought back 

 from the islands of the Indian Ocean by the 

 expedition under the leadership of Mr. J. 

 Stanley Gardiner continue to furnish material 

 for reports by different specialists. Eeports 

 22 to 33, now before us, are the following: 

 Nemerteans, by E. C. Punnett andC. Forster 

 Cooper; Echinoderma (exclusive of Holothu- 

 rians), by F. Jeffrey Bell; Cirripedes, by A. 

 Gruvel; Ehynchota, by W. L. Distant; Am- 

 phipoda Hyperiidea, by A. O. Walker; Land 

 and Freshwater Mollusca, by E. E. Sykes; 



Marine Mollusca, by J. Cosmo Melvill ; Alcyo- 

 narians, by J. Arthur Thomson, E. S. Eussell 

 and D. L. Mackinnon; Cephalochorda, by H. 

 O. S. Gibson; Crustacea (Penseidea, Steno- 

 pidea and Eeptantia), by L. A. Borradaile; 

 Lepidoptera (exclusive of Tortricidae and 

 Tineidae), by T. Bainbrigge Fletcher; Poly- 

 chasta, part 2, by F. A. Potts. Perhaps the 

 most interesting is that of Mr. H. O. S. 

 Gibson, on the so-called genus Amphioxides, 

 which appears to consist of larval forms of 

 Branchiostomids. The expedition brought 

 back abundant material, representing Gold- 

 schmidt's species A. pelagicus and A. valdivioe, 

 which are believed to belong to Asymmetron 

 and Heteropleuron, respectively. Mr. Gibson 

 gives a very elaborate discussion of their 

 structure and aiBnities, but shows that more 

 material and observations are needed to com- 

 plete the chain of evidence. 



The land fauna of the Seychelles is of great 

 interest, owing to the position of the islands 

 between Africa (and especially Madagascar) 

 and India. There are rather numerous pre- 

 cinctive birds and reptiles, and one would 

 expect the various groups of invertebrates, 

 when thoroughly collected, to yield many re- 

 markable species. Mr. Sykes gives us a list 

 of the Mollusca, describing three as new. He 

 remarks : " Very little can be at present stated 

 as to the origin of the fauna : Streptaxis shows 

 African influence, Stylodonta that of Mada- 

 gascar, while Cyathopoma is mainly Indian. 

 The connection with any mainland must have 

 been at a very remote period, from the well- 

 marked forms (Acanthennea, Priodiscus, etc.) 

 now found." The list given is incomplete, 

 from the omission of five species of Yeroni- 

 cella. Mr. Distant lists the Ehynchota or 

 Hemiptera of the Seychelles, which so far in- 

 clude 51 Heteroptera and 12 Homoptera (not 

 counting Coccidse).' Of all these, it appears 

 that five genera and 28 species are ostensibly 

 precinctive, but as the Hemiptera of Mada- 

 gascar are still very imperfectly known, no 

 particular significance can attach to these 



' This enumeration includes not only the Sey- 

 chelles, but the Farqunar, Amirante and Coetivy 

 groups. 



