Rate of Growth in Gobius minutus. 219 



specimens, averaging 4 mm., obtained at Station V., Moray- 

 Firth, on September 12th, 1890, may be mentioned. Thus 

 the spawning period extends over many months. However, 

 as the appended tables will show, the larval forms occur most 

 frequently in the summer months, and. reach a maximum in 

 June. There are no ova of G. minutus in the collections on 

 which the present work is based, but they are said by the 

 authors above mentioned to measure ]'l to 1*2 mm. along the 

 major axis*. The smallest larval forms in the collections 

 measure 1'5 mm.; these were obtained in a bottom-net at 

 St. Andrews on June 26th and 27th, 1891, and must have 

 been newly hatched. There is undoubtedly considerable 

 variation in G. minutus, but it may be stated at the outset 

 that, so far as the writer is aware, the majority of the speci- 

 mens with which this paper deals belong to the typical race, 

 i. e. G. minutus major, lleincke, as opposed to the estuarine 

 race, which finds its extreme in the variety G. microps, 

 Kroyer. The lack of pigment (owing to the fact that the 

 majority of my specimens were preserved in spirit) renders 

 this opinion doubtful, but the size of the largest specimens 

 from the St. Andrews area agrees closely with that given by 

 Holt and Byrne for the typical race, i. e. 80 mm. Most of 

 the specimens from the Clyde area, on the contrary, were 

 preserved in formaline, and have retained their pigment, but 

 in these forms the vertical barred marking characteristic of 

 the estuarine race was not observed, although the length of 

 the largest specimens rarely exceeds 60 mm. 



The appearance and coloration of larval gobies 3-5 mm. is 

 well described by M'Intosh and Mastennan f. As before 

 stated, all the larval gobies were preserved in spirit, so that 

 no further observations with regard to coloration have been 

 made. Holt and Byrne say of the larvae of G. minutus:— 

 u The young when hatched already have their mouths open 

 and yolk-sacs nearly absorbed, and soon attain the form of 

 the adult." These statements are borne out by PI. IX. 

 fig. 1, representing a larval form only 2 mm. in length. It 

 will further be seen that numerous small oil-globules are 

 scattered through the yolk-sac, and that there is a pre-anal 

 fin, though the latter can hardly be described in this case as 

 " considerable" \. The rays of the soft dorsal and anal fins 



* Mr. Holt in an earlier paper (Ann. & Mag. Nat. Hist., July 1890, 

 p. 34) gives the measurement as 1*4 to 1*2 mm. 

 f Op. cit. p. IW. 

 X E. W. L. Holt, Ann. & Mag. Nat. Hist., July 1890. p. 37. 



16* 



