October 24, 1895J 



NATURE 



61; 



OUR BOOK SHELF. 



Ilaiidliook of Grasses; treating of their Structure, 

 Classification, Geograpliical Distri/>i/ti.»i, and Uses, 

 ir/so descritnng the British Species and their Habitats. 

 By William Hutchinson. Svo. Pp. 92, 40 woodcuts. 

 (London: .Swan Sonnenschein and Co. New York: 

 Macmillan and Co., 1895.) 



This is a cheap popular work, adapted for the use of 

 elementary students. There is nothing,' that covers the 

 same field in existence already, and it fulfils its purpose 

 excellently well. It would have been better to have 

 called it ".-^n Introduction to the -Study of the British 

 Grasses," as it only deals in detail with the British species, 

 which are not more than one-thirtieth of the total number 

 of grasses that are known in the whole world. The 



J short introduction explains how easily a collection of 

 dried grasses can be made. The first chapter, called 

 " Structure," gives all the different organs in detail, 

 showing what is the general plan on which grasses are 

 organised, and explaining the general and special terms 

 which are used in describing the genera and species. In 

 the second chapter, which is the longest in the book, 

 the hundred and odd British species are classified 

 according to their localities, and described in detail, most 

 of the common kinds being illustrated by small woodcuts, 

 with dissections. The third chapter is devoted to 

 classification, in which Bentham and Hookers "Genera 

 Plantarum " is followed. The British genera are 

 described in detail, and the characters of the thirteen 

 tribes there adopted, several of which are not represented 

 in Britain, are given. The rest of the book is occupied 

 by a readable account of the geographical distribution of 

 the grasses, especially of the cereals, and an account of 

 their various uses for food, and in other ways. GraiiUnece 

 is one of the most universally distributed of all the 

 natural orders of plants, and, in point of the number of 

 species, is only exceeded by five other natural orders : 

 Conipositcc, Leguniinosce, Orchidea; Melasloiiiacece, and 

 Rubiacece. Between three and four thousand species of 

 grasses are known, and they are classified under three 

 hundred genera. The little book is well written and 

 trustworthy, and no doubt will secure a good circulation. 



Rural Water .Supply. By Allan Greenwell, .^..-VLLCE., 

 and VV. T. Curry, .•V.M.I.C.E. Pp. 210. (London : 

 Crosby Lockwood and Son, 1895.) 



In this \'olume we have an eleinentary work on water 

 engineering, containing a sufficient account of the 

 principles and construction of waterworks to be of real 

 use to engineers, and forming at the same time a good 

 introduction to more elaborate treatises. The volume is 

 based upon a series of articles which appeared in the 

 Builder last )ear, and it contains valuable information 

 upon all matters connected with water supply. It is, 

 indeed, what its secondaiT title represents it to be, 

 namely, "a practical handbook on the supply of water 

 and construction of waterworks for small country 

 districts." The book is full of details on points which 

 are continually before waterworks engineers ; and though 

 these details are mostly rules and formuhe which have to 

 be accepted without being understood, they will be of 

 great assistance in planning schemes of water supply 

 and in carrying out the works. 



■Climbing^ in the British Isles. II. Wales and Ireland. 

 Wales. By \V. P. Haskctt Smith. Ireland. By 

 H. C. Hart. Pp. 197. (London: Longmans, Green, 

 and Co., 1895.) 



Cl.lMliERS will find this little pocket-book an in\alualjle 

 guide to instructive scrambles in \\'ales and Ireland ; 

 but the large number of fatal accidents recorded in its 

 pages is hardly calculated to give other readers the 

 mountaineering fever. On the first two pages of the 



NO. 1356, VOL. 52] 



I book, three fatal falls and one severe accident are noted, 

 and the tale of deaths is sustained throughout the book. 

 To those who arc filled with the desire to climb, this 

 spice of danger only gives zest to the recreation ; and 



I the fact that several lives have been lost in attempts to 

 scale a certain rock, is a sufficient reason for many 

 Englishmen to tackle that rock and endeavour to scale 

 it. In the book under notice, all the essential informa- 

 tion about climbs in Wales and Ireland is given, with 

 thirty-one illustrations (by Mr. Ellis Carr) and nine plans. 

 By means of it, the would-be climber will be able to 

 select his hills and peaks without difficulty, and with its 

 assistance he may do in these islands hill-climbing which 

 will form no mean uart of a real mountaineering educa- 

 tion. The book is primarily intended for those who 

 climb for climbings sake, hence little attention is paid 

 to the geological interest of the rocks and hills described. 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Natitre. 

 No notice is taken of anonymous communications. ] 



The Feeding-Ground of the Herring. 



In his presidential address to .Section D of the British Associ- 

 ation at Ipswich, Prof. Herdman says : — 



" Probably no group of animals in the sea is of so much im- 

 portance from the jioint of view of food as the Copepoda. They 

 form a great part of the food of whales, and of herrings and many 

 other useful fish, both in the adult and in the larval state, as 

 well as of innumerable c/ther animals, large and small. Con- 

 sequently, I have inquired somewhat carefully into their dis- 

 tribution in the sea, with the assistance of Prof. Brady, Mr. 

 Scott, and Mr. Thompson. These experienced collectors all 

 agree that Copepoda are most abundant, both as to species and 

 individuals, close round the shore, amongst seaweeds, or in 

 shallow water in the Laminarian zone over a weedy bottom. 

 Individuals are sometimes extremely abundant on the surface 

 of the sea amongst the plankton, or in shore pools near high 

 water, where, amongst Enteromorpha, the Harpacticida; swarm 

 in immense profusion ; but, for a gathering rich in individuals, 

 species, and genera, the experienced collector goes to the shallow 

 waters of the Laminarian zone. ... In order to come to as 

 correct a conclusion as possible on the matter, I have consulted 

 several other naturalists in regard to the smaller groups of 

 more or less free-swimming Crustacea, such a* Copepoda and 

 Ostracoda, which I thought might [Xjssibly be in considerable 

 numbers over the mud. I have asked three well-known 

 .specialists on such Crustaceans — viz., Prof. G. S. Brady, F.K.S., 

 Mr. Thomas Scott, K.L.S., and Mr. I. C. Thompson, F.L.S. 

 — and they all agree in .stating that, although interesting and 

 peculiar, the Copepoda and Ostracoda from the deep mud are 

 not abundant either in species or in individuals. In answer to 

 the questior which of the three regions, (i) the littoral zone, 

 (2) from low water to 20 fathoms, and (3) from 20 fathoms 

 onwards, is richest in small free-swimming, but bottom-haunt- 

 ing, Crustacea, they all replied the middle region from o to 20 

 fathoms, which is the Laminarian zone and the upper edge of 

 the Coralline. . . . [.Mr. T. Scolt] tells mc that .is the result of 

 his experience in Loch Fyne, where a great part of the loch is 

 deep, the richest fauna is always where banks occur, coming up 

 to about 20 fathoms, and having the bottom formed of sand, 

 gravel, and shells. The fauna on and over such banks, which 

 are in the Coralline zone, is much richer than on the deeper mud 

 around them. On an ordinary shelving shore on the west coast 

 of Scotland, Mr. Scott, who has had great experience in collect- 

 ing, considers that the richest fauna is usually at about 20 

 fathoms." 



It .seems to me that these three specialists, or experienced 

 collectors, have not given Prof. Herdman any information as to 

 whether free-swimming Crustacea, such as Copepoda, arc found 

 in considerable nundicrs over the mud or not, as maintained by 

 Ur. Murray in his concluding remarks in the Summary vt)lumes 

 of the Challenger Report, and I propose to answer the 



