42 PROFESSOR VAN BENEDEN. 



I ought, liowever, to add that having preserved some groups 

 of eggs in jars in order to follow step bj step the modifications 

 which are produced, I never saw the eggs become detached 

 from one another. But it is not possible to keep them indefi- 

 nitely in a living state under these conditions. Although 1 took 

 care to renew the water several times a day, I found it impos- 

 sible to preserve my embryos alive for more than from twenty- 

 four to thirty-six hours. 



Although 1 had no intention, when I went to Villafranca, of 

 occupying myself with the embryology of fishes and the desire 

 of arriving at a solution of the various questions relative to the 

 organisation and development of the Dicyemida left me but little 

 leisure, yet I could not resist the temptation of utilising the 

 beautiful material for study which I found placed in my hands. 

 None of the difficulties which are usually met with in the study 

 of the development of fishes present themselves in this case. 

 The capsule of the eggs is very thin and of perfect transparency. 

 The deutoplasm is constituted by an albuminoid globule which 

 is perfectly homogeneous, hyaline, free from all granulation and 

 limited by a very sharp and j)erfectly regular contour. In the 

 protoplasm of the e^g, whether of the germ or of the proto- 

 plasmic mantle which clothes a part of the vitelline globe, there 

 exists neither fat-globule, nor vesicle, nor formed element of any 

 kind; nothing, in a word, which one could confuse with a cell or 

 a cell-nucleus. 



Yery similar pelagic eggs, belonging probably to a closely- 

 allied species, were observed by Haeckel (1) during his last 

 visit to the coast of Corsica. He has published his researches 

 on the history of their develo|)nient in the second part of his 

 work 'Die Gastrula und die Eifurclmng der Thiere.' lie 

 found the same eggs at Nice in 1S7G. Haeckel did not succeed 

 any better than 1 have done in determining with precision the 

 species to which the eggs which he had under observation are 

 to be attributed. Basing it on the description given by Retzius 

 of the eggs of Gadus lota, Haeckel puts forward the opinion 

 that the fish, the development of which he studied, is a Gadoid 

 allied to the Jiurbot, perhaps a Molella. 



The eggs which have furnished me with the observations of 

 which i am about to give an account ])resent a very great re- 

 semblance to those studied by Haeckel. Found under the same 

 ccmditions, at the same part of the Mediterranean coast, they have 

 very nearly the same dimensions, the same aj)pearance, and 

 the satne conij)osition. At the period of deposition they are 

 agglutinated in masses of various volume and form. The 

 quantity of matter which holds them together is very small 

 indeed, so that one cannot say of my eggs as Haeckel says of 



