70 



SCIENCE. 



[N. S. Vol. III. No. 54. 



evolution of the group. Foi'tunately, these 

 views have proved illfounded, and a more 

 minute and exhaustive study of shell characters 

 in some groups has shown that valuable assist- 

 ance in working out lines of development and 

 the relations of different forms may be obtained 

 by those who properly study the shell, its larval 

 forms and dynamic relations to the organism. 

 No one now doubts the importance of such 

 studies in such large groups as the Ammonoid 

 and Nautiloid cephalopods, the Volutidse among 

 gastropods, and the Naiades among pelecypods. 



The study of the stages of evolution of the 

 larval characteristics is a field hardly entered 

 upon and promising rich returns to the student, 

 and, for the paleontologist, deprived of all 

 anatomical aid in tracing the lineage of peculiar 

 extinct genera, the necessity of study of the 

 nepionic stages of the fossils is fundamental. 



For these reasons all contributions to our 

 knowledge of existing larval forms are welcome, 

 especially with such a wealth of illustration as 

 in the present volume. Among the more im- 

 portant matters in it we find a very full account 

 of Janthina, iu both adult and larval states ; of 

 larvee of the type of Echinospira, belonging to 

 the Lamellariidae; of the Macgillivrayia type 

 like those of Tritonium and Dolium; of the 

 Sinusigera type, including many genera of 

 Rhachiglossa and Toxoglossa ; a general dis- 

 cussion of the conditions of larval existence 

 and their bearing on the characters developed; 

 some account of pelagic nudibranchs, such as 

 Glaucus and Fiona ; a table showing the quanti- 

 tative results of the dredging or towing nets ; 

 and a bibliography of literature consulted. 



The only criticism which suggests itself is 

 that it would be more convenient for those who 

 have to use the book if the magnification of the 

 figures was stated in units of the whole length, 

 rather than merely indicated by the name and 

 number of the objective used for the microscopic 

 work. W. H. Dall. 



The Structure and Development of Mosses and 

 Ferns. By Douglas Houghton Campbell, 

 Ph.D., Professor of Botany in the Leland 

 Stanford, Jr., University. 8vo. Pp. 544. 

 London, Macmillan & Co. 1895. 

 The results of the long continued and patient 



work that Dr. Campbell has been publishing 

 from time to time on the Pteridophytes have at 

 last been brought together, with the results of 

 a large amount of new work on the Hepaticae 

 and other Bryophytes, and the whole results in 

 a large volume issued by the well-known pub- 

 lishers, Macmillan & Co., under the above at- 

 tractive title. 



The first thing to be noted as praiseworthy in 

 the book is clearness and simplicity of expres- 

 sion, for while dealing with a recondite subject 

 and using strictly technical terms, the book 

 reads smoothly and is devoid of that stilted 

 language that too frequently characterizes 

 works of this nature. The logical arrange- 

 ment of the matter follows closely on the sim- 

 plicity of style and these two features are suflB- 

 cient to recommend the work to the learner, 

 for too many are repelled from many a fascina- 

 ting subject by the nature of the language and 

 the lack of a systematic arrangement of the 

 matter. 



But beyond these questions of form the sub- 

 ject-matter is fresh and direct from the hand of 

 the laboratory worker. The studies on which 

 the work is primarily based were made from 

 American plants, many of them plants from 

 the Pacific coast that have never before been 

 studied from the developmental and morpho- 

 logical standpoint. Riccia hirta, Fimbriaria 

 Californica, Porella Bolanderi, Anthoceros fusi- 

 formis, Ophioglossum pendulum (from Hawaii), 

 Botrychium Virginianum and Marsilea vestita 

 are only a few of the new plants that have 

 been called in to contribute their life history 

 for the verification and often modification of 

 the work of Hoifmeister, Kny, Gcebel, Stras- 

 burger and others made on similar plants of 

 central Europe. As one result of this new 

 study. Dr. Campbell has given us a fresh supply 

 of illustrations in place of the standard stock 

 that has become threadbare from long usage in 

 European and American text-books. If some 

 of the illustrations are not quite so clear cut as 

 some that have appeared in certain European 

 publications of recent date, they more than 

 make up for this in their freshness and accuracy 

 for they represent exactly the conditions met 

 with by the author and have not been filled in 

 by the imagination, as is sometimes the case. 



