109 



ular valvos as showing thx*ouf;h the vessels of the ventricle, 

 X about 20. 



Fig. 55. Longitudinal section of the ventricle and ves- 

 sels oi" a specimen 4 inin. long. Tlio a t-rows indicate the 

 course or the blood. The posterior adductor ntuscle, and the 

 wall oi" the stomach represented in part, x :"44. 



Fig. 56. Longitudinal section of the anterior part of 

 the ventricle and vessels of a specimen 10 cm. long, x 544. 



Fig. 57 A, group Oi' cells from the main portion of the 

 style slieath, and 57 E, from the tubiilar portion, x 1150. 



Fig. 58 A, group of cells from the liver which show the 

 usual liver structure, and 58 B, from its modified portion. 

 X 1150. 



Fig. 59. Nervous system of nev/ly-attached larva, showing 

 the pleural ganglion still separate from the cerebral, and 

 the visceral ganglia still wide apart, x P>60 , 



Fig. (50. Nervous system of adult, dorsal view, except 

 that the pedal ganglia are shown more from behind. 



Fig. Gl. Section of the osphradium, vertical to the sur- 

 face, to show the structure of the osphradium and the two 

 types of sensory cells, witli their brush-like tenninations. 

 X 2420. 



Fig. 62. Tangential section o^ ^hr> osvihradium, to s'r.ow 



