>90 GEOLOGICAL SURVEY OF THE TERRITORIES. 



EXPLANATION OF PLATE XXXVIII. 



Lettering. 

 a', first pair of antennae. 

 a^, second pair of antennae. 

 md, mandibles. 

 mx^, first pair of masillce. 

 inctf^, second ]oair of maxillse. 

 pd', first pair of tlioracic feet. 

 2?&", second pair of thoracic feet. 

 th. I, tlioracic feet, 

 at. /, abdominal feet. 

 OB, ossophagns. 

 ep, epithelium of stomach. 

 p. d, procephalic or antennal lobe. 

 si, stomach. 



Fig. 1. Embryo of Neialia geojfroyi in the Nauplius stage. 



Fig. 2. The same, farther advanced, with the -rudiments of the cephalic and first two 



thoracic appendages and the hind gut. 

 riG. 3. The same, still more advanced, the biramous thoracic feet developed. 

 Fig. a. Embryo of the same nearly ready to hatch. 

 Fig. 5. Embryo at the time of hatching. 



Figs. 1-5 copied from Metschnikofi'. 

 Fig. 6. Embryo of Schizopod Pseudomma roseum. Copied from Sars. 



