August 24, 1900.] 



SCIENCE. 



311 



have been previously incubated. Blasto- 

 derms vary from 4 to 11 mm. in diameter. 



Incubation 8. Nine eggs at 24.5 degrees 

 C. for 6 days, li hours gave one primitive 

 streak 1.5 mm. long as the greatest devel- 

 opment. Blastoderms vary from 4 mm. to 

 1 cm. in diameter. 



Incubation 9. 11 eggs at 24 C. for 6 

 days, 19 hours. Blastoderms vary from 

 5.4 mm. to 7 mm. in diameter. With the 

 exception of a degenerated 2-days chick 

 only 4 of the 11 blastoderms showed a trace 

 of the primitive streak. 



The Fishes of Africa as Exponents of former 

 Geographical Conditions : By Theodore 

 Gill, Smithsonian Institution. 

 The fishes of Africa represent two very 

 different elements. One is composed of 

 Asiatic types ; the other of South American 

 types. The latter indicate a former con- 

 nection direct or mediate with South 

 America ; the latter are in conformity with 

 the present association of the continents. 



The Moringuid Eels and their Geographical 

 Distribution: By Theodore Gill and 

 Hugh M. Smith, Washington, D. C. 

 The Moringuid eels are remarkable for 

 their very elongate body dispi-oportionally 

 elongated abdominal cavity, and remote- 

 ness of the heart from the branchial ap- 

 paratus. The family had been supposed to 

 be peculiar to the oriental seas, but a recent 

 discovery has directed the attention of the 

 authors to the American eels generally and 

 it was recognized that 3 genera previously 

 associated with Murjenesocidae really be- 

 long to the Moriuguidse. Stilbiscus indeed 

 is a synonym of the type genus, Moringua. 

 A new species of the related genus Apthal- 

 michthys has also been added to the Amer- 

 ican fauna. 



Tlie History of the Word Mammalia : By The- 

 odore Gill, Smithsonian Institution. 

 The word mammalia was first introduced 



by Linnseus, in 1758, as the expression of 



a concept first appreciated by him. It was 

 formed in analogy with animal. Simple as 

 the explanation is it has never been recog- 

 nized. 



C. H. ElGENMANN, 



Secretary. 



SCIENTIFIC BOOKS. 

 An Introduction to the Study of the Comparative 



Anatomy of Animals. By Gilbert C. Bourne. 



Vol. I. London, George Bell & Sons ; [New 



York, Macmillan]. 1900. 16mo. Pp. xvi + 



269. Price, $1.10. 



It is rather difficult to form an adequate es- 

 timate of a work from its first VKDlume. It is 

 not easy to get the author's perspective ; and 

 then there are so many things left in doubt 

 which the remainder of the series may straighten 

 out. The plan of Mr. Bourne's work is pecu- 

 liar. It starts out with a general chapter 

 which deals with fundamental morphological 

 and physiological principles, and then takes up 

 the frog, treating first of its anatomy and then 

 of its histology. This last subject leads up to 

 a consideration of the cell, and this is followed 

 by a consideration of the early history of the 

 frog. The remainder of the book is occupied 

 by detailed accounts of several Protozoa, Hydra 

 and Obelia. We are promised that the second 

 volume will deal with the Ccelomate Metazoa. 



A rather careful examination shows few 

 errors, yet there are several points on which 

 the student will need fuller information than 

 the volume affords. Thus terms are used 

 without explanation or definition, while here 

 and there comparisons are made which will 

 not be intelligible because the student has no 

 information as to one of the subjects of com- 

 parison. While finding fault it might be well 

 to ask why it is that many English writers 

 persist in the use of the terms epiblast, meso- 

 blast, and hypoblast. It is not easy to see how 

 the work can be used in courses of comparative 

 anatomy as usually given in America, except 

 as a reference book for occasional use. Its 

 wealth of detail concerning forms usually 

 studied in the laboratory would be seized upon 

 by many students as affording answers to the 

 questions which they are asked and are ex- 

 pected to obtain from the animals themselves. 



