154 J. T. CUNMNGHAM. 



much in size or stage of development. Tiiese eggs are close 

 to one another, only separated by the thin membranes of the 

 follicles containing them, the interstices being occupied by 

 strands of connective tissue and blood-vessels. I have pre- 

 pared sections from three specimens which died in the aqua- 

 rium of the~ Laboratory of tlie Marine Biological Association 

 at Plymouth, and the history of which is recorded in my 

 paper on the conger in the ' Journal ' of the Association, 

 vol. ii (new series). 



The structure of the largest and most advanced eggs in 

 these sections is shown in fig. 33, which is from a preparation 

 made from material preserved in corrosive sublimate and 

 acetic acid. It will be seen that the vitellus has shrunken 

 away from the vitelline membrane, which is very thin. The 

 follicular epithelium also lying upon the vitelline membrane 

 is very much thinner than in the eggs of other fishes at a 

 similar stage. The yolk consists of small vitelline globules 

 which extend throughout the extra-nuclear region, and are 

 closely crowded together. There are also a number of scat- 

 tered oil vacuoles, situated principally about midway between 

 the germinal vesicle and the surface of the egg. The germinal 

 vesicle is somewhat contracted, so that there is an artificial 

 separation between it and the surrounding vitellus. There 

 is no nuclear membrane, the nucleus consisting of a finely 

 granular or really reticulate achromatic substance containing 

 a small number of deeply-stained nucleoli. 



It is an interestiug question whether any inferences can be 

 drawn from the structure of this nearly ripe egg, concernicg 

 the condition of the ripe egg after deposition. The fact that 

 among pelagic eggs none have been obtained in British waters 

 which could possibly belong to conger or eel, is an obstacle to 

 the supposition that the egg of the conger may be pelagic. Yet 

 the structure of the egg, as above described, certainly agrees 

 rather with that of nearly ripe pelagic eggs than with that of 

 those which are heavy and adhesive. Eggs of the latter kind 

 generally have a thick vitelline membrane, showing a division 

 into two layers, while that of the conger is remarkably thin. 



