June 6, 1919] 



SCIENCE 



543 



inspection of experimental plots at Glen Head 

 and in visiting a few of the large truck farms 

 for which Nassau County is famous. An 

 evening meeting will be held at Xew York 

 City. 



The experimental test plots consist of plant- 

 ings of healthy, mosaic, and leaf roll seed 

 tubers obtained from northern and central 

 New York, Vermont, Maine, Long Island, 

 Prince Edward Isle, and Bermuda. Eecords 

 of the behavior during 191S of the parent 

 plants will be compared with the behavior this 

 year of the progeny. Much of this seed has 

 been planted under the direction of patholo- 

 gists who have been investigating these dis- 

 eases. An opportunity will also be afforded to 

 compare fields planted with seed from the 

 north and with Long Island grown seed; of 

 fields planted with mature and with immature 

 seed. 



Noted potato pathologists from the United 

 States, Canada and Bermuda will be present 

 to explain the various tests, to point out the 

 characteristic symptoms, and to discuss the 

 results observed here as well as other experi- 

 ments they have conducted. The bearing of 

 these observations and studies on seed certifi- 

 cation will be given consideration at the con- 

 ferences held during the tour. Invitations 

 have been extended to a pathologist of Eng- 

 land, of Ireland and of Holland, and some as- 

 surance has been received that one or more 

 of these men will be present. It is expected by 

 means of these observations and discussions 

 that considerable light will be thrown upon 

 the nature and behavior of those serious and 

 baffling diseases and that thereby measures 

 for control will be better understood. 



Every pathologist interested in potatoes or 

 in these particular types of diseases should 

 plan, if possible, to attend, for the occasion is 

 unusual in material available for study and 

 in instruction presented. Horticulturists, 

 agronomists and other persons interested are 

 invited to join the pathologists. 



Persons planning to attend should at once 

 inform the writer in order that accommoda- 

 tions may be reserved for thorn. The farmers 

 of Long Island have generously offered to pro- 



vide the means of transporting the party about 

 the island. 



M. F. Barrus, 

 Chairman, Committee of Arrangements 



SCIENTIFIC BOOKS 

 Appendages of Trilobites. By Charles D. 

 Walcott. Smithsonian Misc., Coll., Vol. 67, 

 No. 4. Cambrian Geol. and Pal., TV., De- 

 comber. 1918. pp. 115-216 + index. Pis. 

 14-42, Text Figs. 1-3. 



In this recent paper Dr. Charles D. Walcott 

 summarizes his investigations of the append- 

 ages of trilobites during the past forty-five 

 years, a research undertaken in pursuance of 

 a promise made to Professor Louis Agassiz in 

 1873. Since that time, he writes, " I have 

 examined and studied all the trilobites that 

 were available for evidence bearing on their 

 structure and organization." 



His sunnnary of 1881= is reviewed and cor- 

 rected, together with later papers discussing 

 his various discoveries in this subject.^ The 

 highly organized trilobite. Xeolenus serraius 

 (Koniinger). from the Burgess shale quarry 

 opened by Dr. Walcott, near Field, B. C, 

 several years ago, shows most graphically in 

 the ten plates devoted to its illustration the 

 highly specialized development of appendages, 

 which is also figured in plates of the Ordo- 

 vician trilobites, Isotelus, Triarthrus, Caly- 

 mene and Ccraurus. In the figure of Neolenus 

 the appendages include antennules, caudal 

 rami, endopodites, epipodites, exopodites, ex- 

 ites and protopodites. The evidence of ap- 

 pendages is supplemented by numerous figured 

 sections of Ceraurus and Calymene. 



2 The Trilobite : New and Old Evidence Relating 

 to its Organization, Bull. Mus. Comp. Zool., Cam- 

 bridge, Mass., Vol. VIII., No. 10, 1881, pp. 191- 

 224, Pis. I.-VI. 



3 Proc. Biol. Soc. Washington, Vol. IX., 1894, p, 

 94. Smithsonian Misc. CoU., Vol. 57, 1912, pp. 

 164, 208, PI. 24, Figs. 1, la. Idem, 1911, PI. 6, 

 Figs. 1, 2; 1912, PI. 24, Figs. 1, la; PI. 45, Figs 

 1, 2, 3, 4. Text-book Pal. (Zittel), Eastman 2d ed. 

 1913, Vol. I., p. 701, Fig. 1,343, p. 716, Figs. 1,376 

 1,377. Smithsonian Mite. Coll., Vol. 57, 1912, pp 

 149-153. 



