i4cS 



SPECIES XX. 



On several occasions an egg was procured of comparatively 

 large size and with a large peri vitelline space. It ranged from 

 2 '97 to 2 "64 mm., the perivitelline space being a little over 

 one-fifth of this total diameter. Only the yolk of the egg is 

 visible in the water to the naked eye, so that they may readily 

 be mistaken for much smaller eggs. The yolk was characterised 

 in nearly all cases by vesiculations, showing on its surface as 

 polygonal honeycomb-like markings. 



Development was comparatively slow. Some eggs which 

 were procured on August 20th, with embryos about half the 

 cnxumference of the yolk, hatched out on the 28th. 



The embryo appears round the yolk as a series of globular- 

 looking myotomes. Shortly afterwards, with the growth of the 

 embryo, the yolk is drawn out into a lenticular-shaped mass, 

 touching the outer envelope at its ends. The movements of the 

 embryo were somewhat peculiar. After a long period of rest, 

 it would suddenly make a spasmodic wriggle, which often com- 

 pletely reversed its position in the longitudinal direction. 



The larva when hatched out proved to be well characterised. 

 There was an entire absence of pigment ; the yolk was drawn 

 out so that it extended over more than half the total length of 

 the animal. The anus was situated midway between the yolk 

 and the extremity of the tail, and the notochord was multi- 

 columnar (Plate IX, fig. 51). 



The eggs were procured at some distance off Cape Point, as 

 follows :- — Cape Point, N. 50^ E., 34I miles — by townet at sur- 

 face ; and Cape Point, E. \ N., 34^ miles — by townet at surface. 



In specimens preserv^ed in formalin, the perivitelline space 

 sometimes becomes opaque and the }'olk disintegrated, but 

 the eggs are readily recognised. 



SPECIES XXI. 



This egg is readily recognised on account of its large size 

 (.1."2— 4 mm.). It has a clear and glassy appearance in the water. 

 Under a low power of tlie microscope it is translucent, and 

 showed a number of polygonal markings. No oil globule is 

 present. 



Development was remarkably slow. One procured on the 

 20th August, and showing no trace of an embryo, showed the 

 first traces of the embryo on the 24th. On the 28th, the 

 embryo was less than quarter the circumference of the egg. The 

 egg did not float ; perhaps, however, on account of small particles 

 of foreign matter adhering to it. On the 4th September the 



