676 PROFESSOR W. C. M'INTOSH AND MR E. E. PRINCE ON 



organs were so little developed as to form two rounded cords. From the fact that no 

 definite series of pelagic ova has been found previous to the appearance of the larval 

 forms, the ova would appear to be demersal. 



Gobius ruthensparri. — In a female specimen about 3 inches long, obtained on 25th 

 January 1886, the ovaries were found to be small, though the ova were sufficiently 

 developed to be visible to the naked eye. Under the microscope, ova of various stages 

 were seen, the largest being about a line in diameter. A germinal vesicle was present, 

 and the central region of the egg was filled with well-marked globules (yolk). 



Centronotus gunnellus. — Like Zoarces viviparus, this species is characterised by the 

 presence of a single unpaired reproductive mass in the form of a median band between 

 the intestine and the abdominal roof. Unlike Zoarces, however, the male organ of the 

 gunnel is also unpaired. In Day's recent work on British Fishes the following note upon 

 the spawning of this species occurs (No. 51, vol. i. p. 210) : — " Nilsson states that its 

 spawn is deposited in November. Mr Peach, however, in June believed he discovered 

 the spawn of this fish in Fowey, in Cornwall." At St Andrews, where it is abundant, 

 frequent examination of the reproductive organs supports Nilsson's observations. In the 

 earlier part of the year (February) the ovaries of the female are very slightly developed, 

 minute ova at various stages occurring in the follicles. In May the male elements are 

 less prominent than the female, for the ovary is the larger organ. In many the structure 

 is in a state of degeneration, large fatty globules and other granules taking the place 

 of the sexual elements. The ova at this time still show great variation in size, the 

 germinal vesicle being also present and unaltered. Towards the end of November 

 females, though of small size, present a large, clavate ovary, tapering from the liver in 

 front to a point behind the anus. The ova are now readily seen by the naked eye, and 

 those on the surface are of nearly uniform size, viz., about # 043 in diameter. Several 

 oil-globules ("012 in diameter) occur in the larger ova, and the yolk is opaque on 

 account of the abundant straw-coloured, almost opaline, yolk-spherules. Outside the 

 ovary is a transparent membrane, apparently continuous with the interstitial connective 

 tissue, and not readily removed from the surface. The smaller ova are finely granular, 

 and in some (the larger) small oil-globules are present. 



The ova of this species after deposition seem to have been first observed by Mr 

 Anderson Smith,* a member of the Fishery Board for Scotland. He found them, 

 probably on the west coast, from February to April. At St Andrews they have hitherto 

 been obtained amongst the rocks in March, masses about the size of a walnut (as Mr Smith 

 states) occurring in the holes of Pholas, the adults in each case being coiled beside 

 them. The ova adhere together like those of Cottus or Clupea harengus, and have 

 a diameter of '076 inch, while the oil-globule measures "0166 to "016 inch. In 

 those nearly ready to hatch the zona radiata is somewhat tender, and presents the 

 usual laminated appearance. It is also most finely and regularly punctate, after the 

 fashion of wire-cloth of great tenuity. The ragged margins especially exhibit the 



* Quoted by Mr Cunningham, op. tit., p. 125. 



