J 94 



filled with a _i4raiuihir mass in which were scattered manv 

 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 surroimding it. 



The diameter of the egg and general appearances were not 

 of course sufficient to identify these two lots of eggs, and as 

 •development proceeded in the younger lot appearances presented 

 seemed to indicate that they belonged to a different fish. 

 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 embryo. Ten days after this a marked 

 difference was observed, the lines of pigment, which were found 

 to have apparently 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 II, tig. 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 

 were 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 only a few divisions of the germinal 

 disc, and had therefore probably been newly deposited. 

 Seventeen days afterwards the first ova hatched out. 'J'he 

 period of development in the egg is therefore very much 

 longer than that of any of the pelagic eggs which usuallv 

 hatched out in 2 days at the same temperature. 



The newly hatched embryo (Plate 11, lig. 20) has therefore 

 ;i 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. 



