April 17, 1890J 



NATURE 



557 



the existence of local conditions whose action upon types 

 of a more plastic nature than that of the series of forms 

 so far collected would probably result in new morpho- 

 logical developments." Mr. Sladen further throws out 

 the suggestion that the Mergui area " may be looked 

 upon as a moulding ground wherein Malayan types 

 assume a modified form." A description of the physical 

 conditions prevailing in the localities where the Asteroidea 

 were collected is contributed by Dr. Anderson, and adds 

 much to the value of this paper. The paper on the 

 Mammals, Reptiles, and Batrachians is by Dr. Anderson, 

 the three classes being represented by 23, 53, and 12 

 species respectively. The whole of the second volume, 

 containing over 300 pages and 19 plates, is devoted to 

 the Crustacea, the .author entrusted with this order 

 being Dr. J. G. de Man, of Middleburg, Netherlands. 

 It should be added that this part of the work relates 

 only to the stalk-eyed Crustacea. 



The names of the different specialists who stand re- 

 sponsible for their respective contributions are sufficient 

 guarantee that Dr. Anderson and the Calcutta Museum 

 have been the means, aided largely by the Linnean 

 Society, of giving to the public a substantial and trust- 

 worthy contribution to the natural history of a much- 

 neglected group of islands. The proximity of the archi- 

 pelago to the main land of course precludes the possibility 

 of expecting much in the way of insular forms. There is 

 one paper, however, contributed by Dr. Anderson, and 

 forming the second part of the first volume, which wiil be 

 read with interest by anthropologists, as it contains a de- 

 scription of a peculiar race of sea gipsies called " Selungs," 

 who frequent the archipelago and inhabit many of its 

 islands. These people appear to be sufficiently distinct 

 from those of the main land to warrant their being re- 

 garded as an insular race, probably having Malayan 

 affinities. At any rate, all that we know about them at 

 the present time is contained in the paper referred to, 

 which is accompanied by two photographic groups of the 

 people, a photograph of their boats, and a lithographed 

 plate of their weapons and utensils. There is also a 

 vocabulary of their language, which, according to General 

 Browne, bears not the slightest affinity to Burmese, but 

 which Dr. Rest reports to be distinctly Malayan. 



R. M. 



HO W TO KNO W GRASSES B Y THEIR LEA VES. 

 How to know Grasses by their Leaves. By A. N. M'Alpine. 



(Edinburgh : David Douglas, 1890.) 

 nPHIS little book will be a valuable aid to agriculturists 

 *- and agricultural students. It is small, and adapted 

 for carrying in a side pocket. It comes out seasonably, 

 as the time is fast approaching in which its teaching may 

 be verified in the field. It fills a gap in our know- 

 ledge of grasses, as botanists usually decide species by 

 the inflorescence, rather than by the leaves. Colour, habit 

 of growth, and form of leaf, are, we know, somewhat 

 variable characters, and cannot always be relied upon ; 

 and in questions relating to the absolute identification of 

 species, no doubt, inflorescence is of first importance. 

 There is, however, a practical knowledge which derives 

 immense benefit from the kind of information contained 

 in Mr. M'Alpine' s work, and after having determined 



approximately the component parts of a pasture in the 

 young state, it is open to the observer to wait for further 

 proof in the spike or panicle, which will in due time appear. 

 A grass-field contains a larger number of species, not only 

 of grasses but of clovers, other leguminous plants, and 

 miscellaneous herbage, belonging to the Cornpositce, 

 Umbellifer<£, Rosacece, and other natural orders. This 

 book treats solely of the grasses, and clearly, and with the 

 help of 200 figures, shows how any person may identify 

 grasses in the leafy stage. " The difficulties connected 

 with the identification of grasses in the flowerless con- 

 dition," says Mr. M'Alpine, " are not at all so great as 

 usually supposed." This is good news from the botanist 

 of the Highland and Agricultural .Society of Scotland, 

 Professorof Botany in the New Veterinary College, Edin- 

 burgh, and translator of Stebler's " Best Forage Plants." The 

 great and varied knowledge of Mr. M'Alpine, is in itself a 

 guarantee that the distinctions he has traced between the 

 blades and stems of grasses are not of a hasty or flimsy 

 character. Many of them are new to us, but others we have 

 noticed ourselves, and know them to be correct. Any one 

 furnished with a copy of this little book, and a small 

 magnifier, will find that an additional interest will be com- 

 municated to walks in the fields, and the question as to 

 the nature of the growing herbage of pastures may be 

 satisfactorily answered. An eye trained to observation 

 will be able to detect slight differences better than the eye 

 which sees not, but we feel confidence that a careful 

 examination of the plates and the letterpress of this little 

 book will, if used in the field, be in itself a training in 

 habits of observation. The book should be in the hands 

 of every agricultural student, as it in due time will become 

 the basis of questions at examinations. T.he facts that 

 Mr. M'Alpine is himself a teacher, and that Prof. Wallace, 

 of Edinburgh University, has written the preface, point to 

 this conclusion. 



The price for so small a book (3^. 6d.) certainly appears 

 very heavy ; but if it is called for in sufficient numbers, 

 we shall doubtless soon hear of a cheaper edition. The 

 demand for books of this class is small, as most farmers 

 do not read more than is good for them, and the subject 

 is not of great interest to the general reading public. 



The classification adopted by Mr. M'Alpine is not 

 that of genera and species. For example, rye-grasses 

 {Lolium) and meadow fescue {Festuca) are grouped to- 

 gether, as having red bases to their stems ; crested 

 dog's-tail grass is peculiar for a yellow stem base ; meadow 

 fox-tail, for a dark or almost black stem base ; Yorkshire 

 fog, for having a white sheath, with red veins. These 

 colours at the base of the stem, taken together with 

 other characters, are used to identify the species, and the 

 grasses which are known by the colours just enumerated 

 form a group described as " characteristically coloured 

 grasses." Group II. includes variegated grasses, whose 

 leaf-blades are composed of alternate strips of white and 

 green tissue. Group III. includes bulbous grasses, with 

 low, flat ribs, such as Timothy grass and false oat grass. 

 Group IV., cord-rooted grasses in hill pastures, such as 

 mat grass and purple Molinia. Group V., acute sheathed 

 grasses, so named on account of their sharp edges. The 

 shoots are quite flat on the sides and the edges acute 

 — such are cocksfoot and rough-stalked meadow grass. 

 Group VII., bitter tasted grasses. Group VIII., bristle- 



