SOME NEW BOOKS 



Earthworms. 



A Monograph of the Order of Oligoch.5;ta. By F. E. Beddard, F.R.S. 

 Quarto. Pp. xii., 769, with 5 plates. O.xford ; Clarendon Press, 1895. 

 Price £-2 2s. 



While the reviewer was preparing his work, " System und Morphologic 

 der Ohgochaeten," he perceived considerable gaps in our knowledge 

 of the morphology of the exotic Oligochaeta, and could refer only to 

 E. Perrier's works, which in this respect may be termed pioneer. 

 Simultaneously, however, with the appearance of the reviewer's book, 

 a pleasing revolution in our knowledge of the higher exotic Oligo- 

 chaeta began, to which, among others, F. E. Beddard, Benham, 

 Bourne, Horst, Michaelsen, Spencer, and Rosa have personally con- 

 tributed. Through the works of these authors we have materially 

 increased our knowledge of the structure of the Oligochaeta, and when 

 the reviewer brought out his " Entwicklungsgeschichtliche Unter- 

 suchungen," in which, especially, the embryology and organogeny. of 

 Rhynchelmis and some Lumbricidae are worked out, the morphology of 

 the Oligochaeta was very much more cleared up than can be said of 

 the organisation of the Polychaeta, Gephyrea, or even of the 

 Hirudinea. It was only necessary, so to speak, to collect several 

 already published data and facts into a whole, in which all that goes 

 under the name Oligochaeta should be placed in a bright light. 

 Beddard took upon himself this work, and in a large quarto volume 

 of 769 pages and 5 plates has sketched an almost complete and correct 

 picture of the organisation of the Oligochaeta. 



The work divides itself naturally into a general part of 173 pages, 

 and a remaining disproportionately larger part, which is given up to 

 a description of the genera and species. The author has manifestly 

 given only a passing attention to the historical representation. In 

 the following pages I shall endeavour to give a short resume referring 

 chiefly to the general part, while I intend to describe the special part 

 in another place. 



The smallest representative of the Oligochaeta is Aeolosoma 

 (about I mm. long), the largest, MicrocJurta vappi and Megascolides 

 austvalis (4 to 6 ft.) ; the number of the segments varies from 6 to 600. 

 The first segment forms a flap or lobe, the prostomium, which in 

 some forms, as Stylaria lacustvis, Rhynchelmis, and Rliinodvilus, is 

 elongated ; in others, as in Deodvilus, it may be absent. The pro- 

 stomium, therefore, cannot be regarded as a special segment, 

 especially as the reviewer has shown that it first develops in the 

 embryos supplementarily as a growth of the first segment. 



With the exception of Anachivta,^ all Oligochaeta are armed with 

 bristles, which rise from the epiblast ; in Anachceta these are reduced to 

 simple hypodermal glands. 



1 Branchiobdella, though generally regarded as a degenerate Oligochaete, is not 

 mentioned in Beddard's work. 



