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* pig ona. Wes gers apes Ra 
z 
1886. | Embryology. | 665 
sidered as mesoblastic cells which have been directly derived 
from the hypoblast. 
On the twelfth day the Malpighian tubes are formed as blind 
outgrowths of the proctodzum, the nervous system is further 
developed, and the first rudiments of the appendages begin to 
appear. Late on this day the animal is hatched with only the 
rudiments of its appendages. 
An investigation of the development of Geophilus by Sograf* 
shows that the early cleavage of the egg of Chilopods is very sim- 
ilar, not only that, but even the formation of the mesoblastic bands 
and ceelomic cavity is similar. Great numbers of cells also 
remain in the yolk in this form until a late period and apparently 
migrate outwards, and may possibly take a share in forming cer- 
man- 
ame 
- ner in Geophilus as in Julus; and, while there is no clearly 
from which the yolk-spherules disappear in the Chilopods, and 
finally the lumen ofthe > appears ded by a secon 
nearly homo 
hypoblastic wall of the mesenteron, and in which free multipolar 
cells are embedded. There occurs a dehiscence of cells into the © 
cœlom from the splanchnic mesoblast investing the mesenteron. 
ese free cells represent blood cells. The process is somewhat 
geneous investment of yolk which lies within the 
u 
has, on ~ 
