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DESCRIPTION OF PLATES. 

 Figs. 2-4, 12, 13 A, 13B, 18-20, 22-27, IZ, 35. 36, 38. 42. 43. 47 and 48 are free- 

 hand drawings made from material studied under the 2 mm. oil immersion ob- 

 jective and compensating oculars 8-12. Except where noted, all the other fig- 

 ures were made from camera outlines and filled in with the 2 mm. oil immer- 

 sion obj. and comp. os. 8-12. 



Reference Letters. 

 a — areaof attachment of anchoring cells c. s. — sensory cell. 

 ax.cy — axis cylinder. cap. g. — capsule of ganglion cell. 



b. r. — refractive body. can. cu. — cuticular canal of spiral organ. 

 bt. V. — blood-vessel. cav. cu^. — outer cuticular cavity. 



c. anch. — anchoring cell. cqv. cu"-. — inner cuticular cavity. 



c. ep. — epidermal supporting cell. cav. ep. — epidermal cavity in tactile ap- 



c. g. — ganglion cell. pendage. 



c. gl. — gland cell. cir. — cirrus. 



