2. A number of collaborators still send us bibliographical data about their 

 recent publications. May we remind those that we only record 

 current or planned investigations? 



3. Collaborators working on the same subject are kindly reques- 

 ted to send in separate forms for each of them personally. 



Subscriptions 



The subscription-fee remains H.fl. 22.75, which corresponds to U.S. $ 6. — . 

 W e want to bring to your special attention that sub- 

 scriptions are supposed to run until further notice. 



We again ask your collaboration to reach those workers in 

 the field of embryology (to be taken in its widest 

 sense) who are not yet included in this issue. Will you 

 please draw their attention to this Service and send us their addresses? 

 General remarks 



The new activity of the Hubrecht Laboratory in the form, of the "Supply 

 and Demand" Service for laboratory animals (see page 156) has met with 

 considerable interest and has developed satisfactorily. We are now able to 

 give you data from a dozen biological supply houses and from nearly two 

 dozens of individual institutes. We hope that this service will markedly 

 facilitate the acquisition of living material for scientific research. 



Since this service will be published annually we request you to send 

 us supplementary data for 1954 in the course of the first half of the year. 

 You will find a form folded in between the first pages of the chapter concerned 

 (page 156). 



The last chapter containing reviews of new textbooks and of revised editions 

 of older ones has been markedly extended, so that we expect that soon a more 

 or less complete survey of new books in the field of embryology and in related 

 fields may be found in this chapter. We decided that this chapter should at 

 any rate be published annually in order to guarantee actuality of the reviews. 



P. D. NIEUWKOOP 



