596 THE SENSES AND SENSORY ORGANS. 



Primitive Chordotonal Organs are typically represented in many 

 larvae, as in Tabanus, most species of Chironomus, and Syrphus. 

 They appear as cords, connected at two points with the integu- 

 ment, like a stretched string, the chordotonal ligament. The 

 chordotonal ligament is connected with the terminal ganglion 

 of a nerve, about midway between its ends (Fig. 74, B}. 



The chordotonal ligament is a fibrous band connecting the 

 nerve ganglion with the integument, and is probably a modifica- 

 tion of the nerve-sheath. It encloses a peripheral nerve-cell, or 

 a group of cells, and one or more remarkable spindle-like quasi- 

 chitinous elements, the auditory rods (Haarstifte). Graber 

 restricts the term ligament to the non-nervous proximal part of 

 the chordotonal organ, and terms the distal part the terminal 

 nerve string ; but it appears to me that the connective nerve- 

 sheath extends in both directions as a ligament, and, for con- 

 venience of description, I have used the term for the whole of 

 the stretched cord which encloses the nerve terminals. Each 



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