674 GEOLOGICAL SURVEY OF THE TERRITORIES. 



EXPLANATION OF PLATE XXX, 



Fig. 1. Branchiima vernalis Verrill. Sixth endite of an anterior leg, showing the nrns- 

 cles and tactile nerves, which arise independently of the central nervous 

 system near the margin of the lobe ; nc^, inner series ; ««*, marginal series of 

 ganglion cells ; on the left side the origin of the setal nerves are seen. 



Fig. 2. Streptocephalus texanus Pack. The 6th endite of an anterior foot. 



Fig. 3. Sireptocephalua texanus Pack. A portion of fig. 2 x i A, showing the mode of 

 termination of the muscle in the middle of the lobe ; the origin of the setal 

 nerves from the inner series of ganglion cells («c) ; s, seta. 



