March 31, 192 1] 



NATURE 



151 



of the family Hydrophilidae, especially on those oc- 

 curring in the vicinity of Ithaca, Some eighteen 

 genera — examples of all of which have been reared 

 bv the author — are dealt with, and keys are given 

 for the determination of the egg-cases, larvae, and 

 pupae (so far as they are known) of this family. 



Among the investigations carried out at the Millport 

 Marine Laboratory, which are recorded in the recently 

 issued annual report for 1919 of the Scottish Marine 

 Biological Association, is one by Mr. R. Elmhirst and 

 Dr. J. H. Paul on the distribution of copper in the 

 iblood and "liver" of the Decapod Crustacea during 

 the moulting cycle. It has been found that as moult- 

 ing approaches the animal accumulates a considerable 

 amount of copper in the "liver," and that this is 

 released into the general circulation when the shell 

 IS cast. The amount of copper present varies ; in 

 the Macrura it may represent 5 per cent, of the ash 

 of the liver ; in the Brachyura only traces are present ; 

 in Lithodes — the position of which is regarded as inter- 

 mediate — the maximum amount is about 2\ per cent. 

 Mr. Elmhirst notes the great abundance in the 

 Laminarian zone of the polyzoon Membranipora meni- 

 branacea, and that animals of various phyla browse 

 on Membranipora, e.g. sea-urchins, starfish and 

 brittle stars, lobsters, crabs, and several molluscs, all 

 of which require lime for building their skeletons or 

 shells. Estimations by Mr. Elmhirst and Mr. J. S. 

 Sharpe show that round the shores of Cumbrae the 

 ■quantity of lime available in the Membranipora in 

 August was equivalent to some 3^ tons of metallic 

 calcium. At that season members of the larger Crus- 

 tacea moult inshore among the Laminaria, and it is 

 significant also that analyses of the ash of Mem- 

 branipora reveal traces of copper. 



I.N the Transactions of the New Zealand Institute 

 <lii., pp. 193-239, 1920), Dr. J. E. HoIIoway continues 

 his studies of the New Zealand species of the genus 

 . Lycopodium with an account of the structure of the 

 prothallus in five species, belonging- to the sections 

 Phlegmaria and Cernua. The structure, which shows 

 considerable variety, is described in detail, tog-ether with 

 the relation of the young plant to the prothallus and 

 the form and distribution of the symbiotic fungus 

 which is universally present, at any rate in later stages 

 of development. The author regards the fungal sym- 

 biont as of great importance. He concludes, from a 

 comparative study of the g-eneral form and structure 

 of the different Lycopodium prothalli, that they are 

 all more or less modified from some primitive type 

 of structure, and that the chief factor in this, modi- 

 fication has been the presence of the symbiotic fungojs. 

 This primitive type was probably a bulky filament of 

 radial build living- at the surface of the ground and 

 containing chlorophyll. The adoption of a fungal 

 habit opened the door to possibilities of modification of 

 this simple type of structure, and the prothallus was 

 able to establish itself in new positions and soils, the 

 different types of habitat resulting in different types 

 of modification of the original structure. When the 

 fungal habit was thoroughly adopted, the early fila- 

 mentous stage became lost,* but in all its forms the 

 Lycopodium prothallus has never departed from its 

 NO. 2683, VOL. 107] 



radial build. It is suggested as possible that the 

 varied aspects of the genus as it exists to-day, in the 

 form and structure of the mature plant, have arisen as 

 a natural consequence from the spread of the pro- 

 thallus to different stations and soils. 



We have received the annual report of the Director 

 of the United States Geological Survey for the year 

 ending June 30, 19 18. During the year under review 

 practically all the activities of the Survey were directed 

 to the prosecution of the war and to problems arising 

 from the war ; research of a purely scientific nature 

 was in abeyance. Much attention was devoted to the 

 search for minerals, the examination of deposits, and 

 the estimate of available reserves. In the effort to 

 meet the urgent demand for essential minerals. Survey 

 geologists visited not only the mining districts of the 

 United States, but also deposits of potash, nitrate, 

 chrome, and manganese in Central and South 

 America and the West Indies. As a further con- 

 tribution to the problems of the day, much considera- 

 tion was paid to the extent to which water-power 

 could, if necessary, replace steam-power. A natural 

 extension of these investigations was the study of the 

 mineral and power resources of the world in general. 

 A number of ingenious diagrams show the work of 

 the various departments of the Survey in relation to 

 the War Departments to which they contributed. 



Since the memorable work of J. W. Judd on the 

 Mesozoic rocks of Scotland the Geological Survey has 

 been able to add many important details, and the 

 discovery of iron-ore in the Upper Lias of Raasay by 

 H. B. Woodward in 1893 has led to a considerable 

 industry. Dr. G. W. Lee now describes ("The Meso- 

 zoic Rocks of Applecross, Raasay, and North-East 

 Skye," Mem. Geol. Surv. Scotland, 1920, 6s.) the 

 western zones in detail, with an interesting series 

 of comparative vertical sections and a geological map 

 of the southern end of Raasay. The iron-ore is 

 oolitic, and passes laterally into siderite. Its com- 

 position is held to ally it with chamosite, the green 

 chloritic silicate described in 1820 from Chamoson, 

 west of Sion, in the Rhone vale. Berthier's original 

 analysis, it may be remarked, has been replaced bv 

 those of Groth, which bring the composition of 

 chamosite into agreement with the ore of Raasay. 

 Mr. S.. S. Buckman concludes from the ammonite 

 fauna that a long interval occurred between the de- 

 position of the oolitic beds and the overlying shales, 

 and Dr. Lee suggests that the mineral change in the 

 former took place during this stratigraphical episode. 

 The presence of green silicates in the oolitic iron-ores 

 of .Arenig age in North Wales, which have been 

 ascribed to the alteration of limestone, renders further 

 research into the origin of the Raasay ore desirable. 



All previous attempts at tabulating chemical 

 analyses of rocks are dwarfed by Professional 

 Paper 99, 1917, United States Geological Survey 

 (" Chemical Analyses of Igneous Rocks," by Dr. H. S. 

 Washington). It is a revised and enlarged edition of 

 Professional Paper 14 (1903), which contained 

 2881 analyses published between 1884 and 1900. The 

 present volume contains 8602 analyses of igneous 

 rocks published between 1884 and 1913, which have 



