A488 A. W. BELLAMY 
neural groove rarely closes and the posterior growing region is almost 
completely inhibited. After this treatment usually not more than 
half of the eggs continue development at all after return to water. In 
a number of embryos no external indications of bilaterality or dorso- 
ventrality were apparent. The embryos approximated a radial type 
of symmetry. ‘Differentiation’ proceeded from an equatorial gastrula 
condition, merely as an apical proliferation of the pigmented cells 
and an elongation, as nearly as one could judge, in the direction of the 
original polar axis. One of these embryos was illustrated in the pre- 
vious report (fig. 20). 
Lithium chloride 
Eggs in late cleavage stages at the beginning of the experiment 
(experiments IV 58 and IV 59). Experiment. IV 58. Eggs in late 
cleavage stages (26 hours after deposition) were placed in m/5 LiCl. 
At intervals of 14, 3, 5, and 18 hours, eggs were removed to water. 
Lot A. (a) 9 hours in LiCl. None of the eges have begun gastrula- 
tion. Control: early gastrula. 
(b) 18 hours in LiCl. Not much advance. About 5 per 
cent show slight wrinkling about midway between equatorial region 
and the apical pole. Many dead or dying. Control in late gastrula 
and early yolk plug stages. 
Lot B. (a) 14 hours in LiCl plus 73 fone in water. Some of the 
eggs show slight. “indications of Pale onal gastrulation (deep wrinkling 
in equatorial region of the egg). 
(b) 14 hours in LiCl, plus 51 hours in water. Embryos 
beginning to plgncane. Behind control. 
Lot C. (a) 3 hours in LiCl, plus 6 hours in water. The eggs are in 
approximately the same condition as those in B (a). 
(b) 3 hours in LiCl, plus 49} hours in water. All of the 
eggs show marked differential inhibition. Neural fold stages with 
large and (probably) permanent yolk plugs. 
(c) 3 hours in LiCl, plus 79 hours in water. Microcephalic 
to anencephalic embryos with ‘fused’ suckers and olfactory pits. There 
are probably some cyclopic embryos among these. Figure 47 illus- 
trates one of the more extreme types obtained under these conditions. 
There is a single olfactory pit and the ventral suckers are reduced to a 
single, small, cone-like protuberance. 
(d) 3 hours in LiCl, plus 103 hours in water. Development 
has continued and the inhibiting effects of the treatment are more 
marked. All of the embryos are now much distended ventrally by an 
accumulation of fluid in the coelome or possibly in the pericardial sac. 
If punctured ventrally with a needle some of the fluid comes away and 
the swelling recedes slightly for an hour or so when, shortly, the dis- 
tention becomes as great asever. Figures 48, 49 illustrate two of these 
embryos. In a number of cases (probably one-fourth), while the 
formation of an embryo has proceeded to some extent, one does not 
readily distinguish, macroscopically at least, between anterior and 
