HABITS AND LIFE HISTORY OF THE TOADFISH. I lOI 



having been effected at Beaufort, I can not give the time definitely; but from 

 three separate broods of early eggs found in the harbor it can be stated that 

 between forty-eight and sixty hours after impregnation the embryonic axis 

 begins to form. 



These structures are for the most part too delicate to be shown in photo- 

 graphs of living eggs. Figure 5, plate cix, shows the board nest frequently 

 referred to. It contains eggs in two stages of development, spreading blastoderms 

 and rod-like embryos, and likewise the crowding always found in the eggs of a 

 large nest. The board and eggs are natural size and all the eggs are shown 

 save a few at each end. If studied with so low magnification as that afforded 

 by even an ordinary reading glass, the young embryos, as yet possessing no 

 trace of fishlike characters, may be seen as axial rods. Close scrutiny will reveal 

 the fact that one end — the future head end — is slightly larger than the other. 



Figure 6, plate cix, shows half natural size another board nest of large 

 size. The embryos here are considerably older than the preceding. The head 

 end has noticeably enlarged, the ventricles of the brain are visible (under a low 

 power), the eye vesicles are forming, the pectoral fin buds are not visible but 

 are clearly marked off at this stage. In short, the embryonic fish is outlined. 



Even a momentary glance at the positions of the embryos will completely 

 negative Ryder's (1886 and 1887) statements that the embryos "invariably" 

 point in one direction. 



By taking the nests out of the aquariums and examining them from day to 

 day the development can be followed step by step. The eye vesicles are formed, 

 the blastopore closes, the pectoral fins grow in size, the tail becomes free, the 

 heart is formed and begins to beat, a vascular system is formed and spreads 

 over the yolk, and, finally, growing dissatisfaction with its narrow quarters is 

 expressed by the little fish through writhings and shiftings of the tail from 

 side to side. 



THE LARVAL TOADFISH. 



Early stage.^Th.^ condition of things described in the preceding section is 

 not destined to continue longer. Presently the time arrives when, the shell 

 having grown weak (rotten is the way my notes put it in numerous cases), the 

 little fish bursts that part over its head and, taking in a mouthful of salt water, 

 passes this back over its gills and is ushered into a new world as the just-hatched 

 larva of the toadfish. 



Usually the shell bursts first over the head and back, setting the head parts 

 free; then the split, continuing backward, sets the tail free. Sometimes, how- 

 ever, the shell bursts over the tail first. In this latter event one will see a wildly 

 waving tail, which by its lashings continues the split forward and uncovers the 

 head. Eventually the shell splits down in several directions and not only un- 

 covers the embryo but the upper half of the yoke as well. 



