PLATE XLI. 



Fig. 1. — Megalatraotus aruanus, Linn. Nephridium laid open, 

 showing the ramification of blood vessels on the 

 glandular mass, and the pores of the nephridial gland. 



Fig. 2. — M. aruamcs, Linn. Pallial complex. 



Fig. 3, — M. aruanus, Linn. Ventricle and fused portion of the 

 aortse. The dotted lines in the tracing show where 

 lies the partition between the two arteries. 



For explanation of letters, see p. 4,50. 



