194 



filled with ;i ^riinular mass in which were scattered many 

 small oil globules. A dividing mass of protoplasm at about 

 the 8 cell stage was also seen. The eggs were separated from 

 •each other by a distance about equal to their own diameter, 

 .and though there was a spreading out of base of the egg 

 ■capsule so that it seemed to be continuous, yet when care- 

 fully removed each individual egg came off independently of 

 those surrounding it. 



The diameter of the egg and general appearances were not 

 ■of course sufticient to identify these two lots of eggs, and as 

 •development proceeded in the younger lot appearances presented 

 seemed to indicate that thev belonged to a different tish. 

 Three days after the egg was procured two thin black parallel 

 streaks appeared near the periphery of the egg at one side, and 

 these proved to be lines of black pigment running along each 

 side of the body of the embrvo. Ten days after this a marked 

 diiiference was observed, the lines of pigment, which were foimd 

 to have apparentlv converged posteriorly and become one on the 

 ventral caudal region, began to break up into stellate black 

 pigment cells. This process was accompanied by the appear- 

 ance of branchings of the black pigment into the surrounding 

 tissue. Plate 1 1, fig. i8 is from a photograph (by transmitted light) 

 'of an embryo at this stage. Branchings are seen from the 

 lateral pigment line, and the ventral caudal streak is becoming 

 broken up. Fig. 19 is from a photograph of the eggs containing 

 embryos at a somewhat later stage of development. They 

 Avere photograped in situ attached to a stone (therefore by 

 reflected light) and show various stages in this process from 

 the two continuous black tracts merging into one, to the 

 •condition in which these parts are broken up into spots of 

 pigment ; in these latter a few yellow pigment spots appear 

 :among the black. A number of large oil globules not 

 observed earlier were seen in the embryos at this stage. They 

 varied in number from one to five. They may be the result of 

 ;the fusion of the minuter globules of the earlier stages. When 

 procured the eggs showed onlv a few divisions of the germinal 

 disc, and had therefore probably been newly deposited. 

 "Seventeen days afterwards the first ova hatched out. The 

 period of development in the egg is therefore very much 

 longer than that of any of the pelagic eggs which usually 

 hatched out in 2 days at the same temperature. 



The newly hatched emJ:)ryo (Plate II, fig. 20) has therefore 

 a totally different appearance to those which hatch earlier. 

 The pectoral fins are well developed. The otocyst is 

 large, extending from the posterior border of the eye to the 

 pectoral fin. The yolk sac protrudes very little, and dis- 

 ppeared on the following dav. 



