159 



and medical scientists, but may be of interest to animal physiologists in general. 

 There is an extensive bibliography of the relevant literature, an authors' and a 

 subject index. 



Chr. P. RAVEN 



, DIE ENTWICKLUNG DES BRAUNEN GRASFROSCHES 



RANA FUSCA, Roesel" 



dargestellt in der Art der Normentafeln zur Entwicklungs- 



geschichte der Wirbeltiere 



1952 



by Dr Fr. Kopsch Georg Thieme Verlag 



Stuttgart 

 69 pages with 2 plates 



The elaboration of this normal table started already in 1898 but was inter- 

 rupted many times by other scientific problems, which had to be given priority. 

 We are the more thankful that Dr Kopsch has finally found time after his 

 retirement at the age of 82 to complete this work and to publish it in the present 

 extensive form. 



The description of the morphological and biological characteristics of the two 

 related species Rana fusca and Rana arvalis, and the systematic survey of the 

 distribution, reproductive period and external features of the full-grown larvae 

 of the european anuran species form a very worthful enrichment with respect 

 to the other Keibcl's normal tables in which the introduction is in general more 

 summary. 



The material for this study was obtained by artificial insemination, and 

 was reared in the laboratory. Although the homogeneity of the material is 

 better guaranteed by this method one cannot be entirely sure that one is dealing 

 with completely ..normal development" since the laboratory conditions (food, 

 light, temperature, etc.) may actually differ from the natural conditions. 



The tabular survey of the development of Rana fusca starts with the two-cell 

 stage as stage 1, whereas all other normal tables start with the one cell stage. 

 This gives rise to a confusing lack of congruency of the various normal tables. 

 The staging used, is, moreover, not adapted to requirements for experimental 

 embryology, but merely represents a purely morphological characterisation of 

 the development of this species. The early stages are rather far apart from each 

 other. 



The description of the external form and the internal organization and diffe- 

 rentiation is very accurate and extensive and is given in a surveyable and clear 

 form. The systematical description of the development of the individual organ 

 systems forms a very valuable supplement to the tabular, chronological survey 

 of the development of this species. 



The absence of the chapter ,,hterature references" is undoubtedly an actual 

 deficiency. 



The figures of the external form of the various stages are good and accurate. 

 The enlargement of a number of them, especially in the general series with 

 enlargement of 2.5 times is, however, too low. Although the general growth is 

 more clearly demonstrated with a reproduction of the various stages in the 

 same magnification, the value of the figures as an illustration of the text is 

 much reduced. The figures on the first plate show clearly that a stage is 

 missing between stage 19 and 20 where the size difference of the successive 

 stages is too pronounced. The varying enlargement of drawing of the same 



