ON EGGS OF MARINE ANIMALS 37 



experiments at least that the failure was due to both, for his 

 published papers clearly give basis to warrant this suspicion. 

 At Naples, Ciona is extremely abundant. 



Phallusia 



Phallusia is also readily obtained at Naples. Its beautiful 

 and transparent egg can be removed from the animal and ferti- 

 lized with ease. Nevertheless, if one intends to work on stages 

 subsequent to the initial fertilization-reaction, one would best 

 use normally laid eggs. 



Amphioxus 



For the early stages in development of the tgg of Amphioxus 

 the worker should collect the animals himself or accompany the 

 collector. At Naples, where Amphioxus is abundant, I was 

 taken by the collectors to the collecting ground. There, using 

 a flat rock as laboratory table, I set up my microscope, glassware, 

 etc. As soon as sand containing the animals in large glass 

 dishes was brought me, I removed them to clean sea-water. 

 The ripe animals discharge their sexual products at once. To 

 insure most normal development, it is necessary to place the 

 shedding female into the dish or vessel in which a male had 

 shed, for, as has been pointed out by older investigators, the 

 eggs do not develop normally if they are allowed to lie in sea- 

 water before inseminated. Occasionally, Amphioxus shed in the 

 laboratory, as LwoflF (1892) first pointed out, a phenomenon 

 which I observed also in 1929. Shedding by Amphioxus in the 

 laboratory has also been observed by Orton at Plymouth, 

 England. (1913-1915.) 



Fundulus 



Three species of Fundulus are used at Woods Hole — hetero- 

 clitus, majalus and diaphanus. Newman (1907 and 1909) has 

 described their normal processes of copulation and egg-laying. 

 If pairs of Fundulus, F. heteroclitus particularly, be isolated, 

 his observations may be readily confirmed. In order to observe 

 copulation and egg-laying by F. majalus in captivity, one should 

 place three or four males with one female (Newman, 1909). I 

 have made these observations on both these species but not on 

 F. diaphanus. These normally laid eggs are the best to use. 



