44,4, BASHFORD DEAN. 
Fic. 37.—Early embryo (77 hours); transverse section of neuron of the 
hinder trunk. x about 160. 
Fie. 88.—Early embryo (95 hours), transverse section ; somewhat in front 
of the undifferentiated tissue of the tail mass. 
Fie. 39.—Early embryo (95 hours), sagittal section of the region of the 
closed blastopore. x about 80. 
Fic. 40.—Early embryo (95 hours); transverse section of neuron in a 
region somewhat behind the hind brain. 
ec. Celenteron. ch. Notochord. dl. Dorsal lip of blastopore. 2. Head 
region (of neuron). 7. Inner germ layer. 4. Kupffer’s vesicle. m. Middle 
germ layer. m’. Merocyte. o. Outer germ layer. 0’. Epidermic stratum of 
the outer germ layer. sc. Segmentation cavity. . Undifferentiated tissue 
of the lip of blastopore. o/. Ventral lip of blastopore. yp. Yolk-plug. 
* denotes the innermost limit of ccelenteron. 
