22 THE AMPHIOXUS. 



weather, insomuch that if these are continually un- 

 favourable, one may have to wait fourteen clays in 

 April for the spawning, and that without result. Any 

 one, therefore, who intends to study the development 

 of the Amplnoxus in Faro, I should strongly advise not 

 to go there until the beginning of May, when one is 

 sure of having some fine clays, in which a very con- 

 siderable amount cf spawning will take place. This 

 will always be found most plentiful when some warm, 

 clays succeed to a somewhat long period of cold and 



stormy weather, and it is on the second or third fine 







day that it mostly begins. 



The fertilization can best be studied by taking the 

 animals out of the sand on the shore on some such 

 warm afternoon, whereupon they will be found to 

 spawn plentifully in the glasses. I have not been 

 able to observe the process more accurately. 



For the study of the segmentation it is better to fish 

 in the sea after sunset in Pantano itself for eggs 

 liberated under natural conditions, and to allow their 

 further development in the glasses. Too many eggs 

 should not be placed in one glass, since otherwise 

 abnormal stages will result. The segmentation itself 

 may only be studied by night. In order to convince 



