408 



NATl Kl: 



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BRITISH MARIS K WORMS. 

 Ray Society: A Monograph of ihc British Antielids. 

 By Prof.'w. C. Mcintosh. F.R.S. Vol. ii., part ii. 

 Polychaeta. Sylliclae to Ariciidae. Pp. 233-524+23 

 plates. (Londiiti ■ nul.in .md Co., Ltd.. kho.) 

 Price 255. net. 



Tins volumi' coiisuuncs .1 iiiriluT inst.'iimciit of 

 I'rof. Mcintosh's large monograph of British 

 Polycha'ts, and its publication raises the hope that 

 the entire work will be completed in a few years. 

 The families described are amonjjst the most interest- 

 ing and the most familiar to naturalists, yet they have 

 probably never received such detailed treatment as 

 is here accorded, with the result that we now have 

 such a survey as Huxley first planned when he under- 

 took professional work. The variety and beauty of 

 this section of the British fauna will be a surprise to 

 most naturalists. 



The most interesting^ points in the volume are the 

 assumption of the "epitokous" stage among the 

 Nereids, and the phenomenon known as " Palolo." 



During their asexual or "atokous" stage, Nereids 

 are provided with similar lobes and bristles on every 

 segment, but when the breeding season ensues many 

 species of this family undergo a metamorphosis. The 

 head and eyes enlarge, the posterior two-thirds of the 

 body grows out sogmentally into new lamellar feet, 

 and these in turn develop long swimming bristles. 

 In this " hetero-nereis " or "epitokous" phase, the 

 two sexes often differ in colour and in habits, and 

 in at least one species there are again two castes of 

 males. The behaviour no less than the appearance 

 of these animals now finds a new expression. Up 

 to this period, Nereis has lived a sluggish life in a 

 burrow. Now as hetero-nereis, he or she strikes out 

 for the open sea, swimming easily and gracefully by 

 rhythmical contractions of the paddles, and discharg- 

 ing broadsides of ova or of milt into the water. This 

 effort is probably the final act of a career, for, carried 

 away by the act of discharge, these pelagic Nereids 

 may rupture and die. 



On this subject the veteran naturalist of .St. 

 Andrews has gathered together his own vast stores oi' 

 information and also those of his fellow-workers. 

 He traces the development of this metamorphosis 

 in all available instances, and collates a great amount 

 of information, not only as to British, but concerning 

 all Polycha?ts that exhibit this phenomenon. 



U'ith regard to palolo, this Fijian word has refer- 

 <iH-r to a peculiar swarming of Polychaets at the 

 surface of the sea. At Amboina, round Japan, 

 on the coast of Florida and Samoa, swarms of 

 Eunicid worms suddenly appear at definite times and 

 disappear as suddenly as they came. The interest 

 of their advent is increased by its coincidence with 

 a certain pliasr oi the moon in two months of the 

 year, October and November in some places, March 

 and April in others. Several genera exhibit this 

 habit of swarming on two or three definitely fixed 

 nights if the weather be clear. By the following 

 morning not a trace of them is to be seen. 



Still more remarkable are the details of the process. 

 During the preceding twelve months these Annelid> 

 NO. 2169, VOL. 86] 



have led a sedentary life, hicim^ a^ lar as is kh .v a 

 in crannies or burrows in r«K:k and coral. No so<jm r. 

 j however, is the moon at full in March x>r in O' 

 as the case may be, than these Eunicids turn 

 in their burrows, twist off their tails, and 

 wriggling on to the surface, the head end : 

 remaining in the burrow. 'The whole mature popu- 

 lation simultaneously perform the act, with the result 

 that the neighbouring water acquires an appearance 

 not unlike that of vermicelli. These severed tail ends 

 arc provided with special ocelli, and swim away laden 

 with ova or with milt, which they discharge with 

 every contraction. In a few minutes disruption is 

 complete, and hf-nce by sunrise the act i$ over. 

 Meanwhile the head-ends, ensconced in their burrows, 

 are already making scar-tissue, and in time reg' : 

 the missing portion. 



Such in brief, though, of course, subj« > I 



modifications, is the meaning of this expression, .and 

 we now ask is there a British palolo, or have we 

 anything of this nature on our coasts? The mono- 

 graph before us gives no certain answer. True, there 

 is a British Lysidice punctata at Guernsey, closely 

 allied to a species that acts palolo elsewhere, but at 

 present such swarming, if it occurs, has escaped 

 observation. .\s to this and many other features of 

 habits, coloration, and development, there is still a 

 wide field for research amongst Polychaets. We trust 

 that the publication of this monograph will stimulate 

 t.> fresh observations on this interesting group. 



Rather unwillingly, a word of criticism must be 

 added, and it is to repeat a request made in the 

 review of the preceding section that appeared in this 

 journal in 1908. It was there urged that the family 

 name of each species should be placed as a headline 

 to one of the two facing pages, preferably the left, 

 and we would also ask for an outline classification in 

 each part .as issued. F"or working purposes the 

 absence of these two simple devices creates an extra- 

 ordinary amount of trouble, and the reviewer is, after 

 careful search, still far from clear as to the classifi- 

 cation of, for example, the Eunicidae. 



In conclusion, the magnificent plates of coloured 

 fifTures reflect the greatest credit on everyone con- 

 cerned in their production. Plate liii., for instance, 

 representing Xercis 7'irens in all its three feet of 

 beauty is a wonderful picture. Prof. Mcintosh is 

 to be heartily congratulated on the completion of such 

 a large section of this great work. 



F. W. Gamble. 



CHEMISTRY FOR MIXERS. 

 Elementary Chemistry for Coal-mining Students. By 

 Prof. L. T. O'Shea. Pp. ix + 319. (London : Long- 

 mans, Green, and Co., 191 1.) Price 6s. net. 

 THE object of this little book is to furnish coal- 

 miners with a knowledge of as much of the 

 science of chemistry and of its applications as they 

 are likely to find useful in their everj-day work. Its 

 contents are thus naturally divisible into two sections, 

 the first giving an outline of chemical principles, and 

 the second a rather more detailed account of such 

 portions of the subject of coal-mining as depend more 

 "illy upon tho above principles. 



