EEPEODUCTIVE ELEMENTS IN MYXINE GLUTINOSA. 69 



cells vary in size, so that the deeper surface of the epithelium 

 is irregular (vide fig. 13a). Amongst the specimens obtained 

 on January 29thj I recognised for the first time a female which 

 had recently discharged its ova. In place of the 19 — 25 large 

 ova which are usually present there were a corresponding 

 number of collapsed follicles; each of these had a slit-like 

 aperture at one end, through which the ovum had been ex- 

 pelled. I found afterwards that similar " spent '^ specimens were 

 present among a lot obtained on December 24th, 1885, and I 

 have obtained them on several occasions since. Thus it is 

 proved that the deposition of ova occurs in Myxine in the 

 neighbourhood of the Firth of Forth during the months of 

 December, January, February, and March. In spite of this 

 discovery, and many zealous attempts, I have hitherto com- 

 pletely failed to obtain a single deposited and fertilized ovum. 



Before recognising the specimens which had quite recently 

 discharged their ova, I had frequently found corpora lutea in 

 the ovaries of old females ; and I have since observed various 

 intermediate stages in the process of absorption of the follicles 

 from which the ova have escaped ; the last stage being that of 

 minute yellow nodules in the mesoarium. 



It is obvious from the above that the eggs described by 

 Steenstrup had escaped from the follicles and remained in the 

 body cavity entangled by their polar processes. The eggs may 

 have been expelled from the follicles naturally, and not yet 

 discharged from the body cavity ; but it is more probable that 

 the eggs were very near perfect maturity in the follicles when 

 the animal was captured, and that the follicles were ruptured 

 by the rough handling the specimen received from the 

 fishermen. 



The yolk-elements are of two kinds ; flat, elliptical, trans- 

 parent and highly refringent discs such as were described by 

 Johannes Miiller, which are doubtless albuminous, and clear 

 spherical-lobed which are probably of a fatty nature (fig. 5). 

 In the very young eggs these yolk-elements are not present, 

 but only fine granules which make the ovum when viewed by 

 transmitted light black and opaque. In still younger eggs, 



