696 



SCIENCE. 



rN. S. Vol. II. No. 47. 



scribes the photogi'aphic technique used. The 

 pictures obtained represent the highest perfec- 

 tion of micro-photography yet reached, espe- 

 cially as applied to i^rotoplasmatic structures. 

 The reproductions are very good, but are not 

 equal to the original negatives in delicacy and 

 clearness. 



The forty phototypes by themselves suffice 

 to give a complete history of the maturation, 

 fertilization and early segmentation of the ovum. 

 Although they are less clear than many pub- 

 lished drawings, these figures unc(uestionably 

 take their place as the best we yet have, for 

 their partial lack of distinctness is more than 

 atoned for by their absolute accuracy and fi-ee- 

 dom from that element of personal interpreta- 

 tion W'hich is unavoidable in every drawing, no 

 matter how conscientiouslj^ made. 



Each phototype is accompanied by a separate 

 explanation of the details shown. This ex- 

 planation, when necessary, is aided by diagrams 

 inserted in the text. 



To the whole is prefixed an abundantly il- 

 lustrated ' General Introduction,'' in which Pro- 

 fessor Wilson gives a summary of our present 

 knowledge of the history of the ovum, so far as 

 it has any bearing on the problems of fertiliza- 

 tion. It would be very difficult to surpass this 

 introduction, owing to its felicitous combina- 

 tion of terseness, clearness and completeness. 



The work takes its place at once as a classic, 

 and is certainly one of the most notable pro- 

 ductions of pure science which have appeared 

 in America. It will be valuable to every biolo- 

 gist, be he botanist or zoologist, be he investi- 

 gator or teacher. There will be many to con- 

 gratulate the author upon his signal success. 

 Charles S. Minot. 



A Monograph of the Order of Oligochseta. Frank 



EvEES Beddard. Oxford, Clarendon Press. 



1895. New York, Macmillan & Co. 4°, pp. 



xii4-V69. 5 plates, 52 wood cuts. 



Mr. Beddard' s Monograph of the Oligochseta 

 has been awaited with no little interest by nat- 

 iiralists, and is the third comprehensive work 

 dealing with the earthworms and their allies. 

 The older work of Vejdovsky (1884) was largely 

 morphological in character and confined chiefly 

 1o forms studied bv the author, while the exten- 



sive work of Vaillant (1889-90) deals with the 

 subject more from the systematic side, embra- 

 cing descriptions of all known forms, but does 

 not include references to literature published 

 later than 1886. The present monograph is an 

 attempt to bring together our knowledge of the 

 entire subject up to the time of publication. 

 It treats of both structure and systematic rela- 

 tionships and incorporates the large list of publi- 

 cations that have appeared during the last de- 

 cade. No account, however, is given of the 

 embryology of the group, owing, the author 

 tells us in his preface, ' to Prof. Vejdovsky's re- 

 cently [1889-90] published Entwicklungsges- 

 chichtliche untersuchungen, which go into the 

 matter with all details. ' The author recommends 

 this work to ' those who are desirous of ascer- 

 taining what is known about the embryology of 

 the Oligochaeta.' It is to be regretted that Mr. 

 Beddard did not include the embryology in his 

 general plan and give us a complete treatise on 

 the Oligochaeta. Even an abstract of Vejdov- 

 sky's work would have added greatly to the 

 value of the volume for the English reader. 



The work is divided into two parts, the first 

 (pp. 1-155) dealing with the anatomy and geo- 

 graphical distribution ; the second, or sys- 

 tematic portion, comprising classification, phy- 

 logeny and descriptions of genera and species. 

 The anatomical portion treats more of the 

 grosser anatomy, comparatively little space 

 being given to histological matters. We miss 

 more particularly an account of the finer an- 

 atomy of the nervous system, the knowledge 

 of which has been enriched by the recent re- 

 searches of Von Lenhossek and Retzius. The 

 part devoted to the discussion of the nephridia 

 is, to our mind, the most complete in the mor- 

 phological portion of the work. 



The author divides the Oligochaeta into three 

 groups ; (1) Aphaneura, (2) Microdrili, (3) Me- 

 gadrili. The Aphaneura correspond to Vejdov- 

 sky's group of the same name, while the Micro- 

 drili and Megadrili are equal in ^'alue to the 

 old divisions Limicolae and Terricolse of Clapa- 

 rede, with the exception that the Aeolosomatidte 

 are separated from the Limicola; and constitute 

 the first group or Aphaneura. The names Mi- 

 crodrili and Magadrili tluis have a broader ap- 

 plication than Benhara's use of them. Among 



