JOUENAL OF ENTOMOLOGY AND ZOOLOGY 195 



on the dorsum. The appendages are also clothed with similar 

 small hollow hairs of the type found so generally among arthro- 

 pods. These liairs are very small in many places but in certain 

 regions as on the ])edipalps they are very long and slender. The 

 liairs are not only hollow but there is a passageway through the 

 chitin below the seta, even in places where the body-wall is very 

 thick. Some hairs are sunken at their bases and the whole 

 neighborhood of the seta elevated into a little knob. Sensory 

 cells of a bipolar type are found at the bases of the hairs in the 

 more perfect sections, these send one process into the base of 

 the hair. These cells were often easily distinguished from the 

 surrounding hypodermal cells by their different shape and 

 staining reactions although the cell process might not extend 

 into the hair. It seems proliable that all the hairs of the animal 

 are sensory and probably tactile. Possibly the long hairs of the 

 pedipalps are also tactile. There was no evidence of any other 

 sense organ except the eyes. In addition to the usual tyi^e of 

 hair just described a simple branched form was found. 



There are two simple eyes, one on either side of the head near 

 the base of the pedipalps. These eyes consist of a thin layer of 

 clear chitin on the outside and a small group of sensory cells 

 below this. On the surface of the cornea of chitin a number of 

 regular knobs of small size take certain stains such as methylene 

 blue. 



Peripheral nerves, such as those supplied to muscles were 

 found especially in longitudinal sections of appendages. These 

 strands were found to be very delicate and deeply staining 

 nuclei were found along the course of the fibers. 



Peripheral Ganglia and Plexuses. No very definite periph- 

 eral centers were found in Chelifer, but in certain dissected 

 specimens in the head and thoracic region there are individual 

 cells and small groups which undoubtedly serve as peripheral 

 ganglia. Some of these seem to be quite intimately connected 

 with the more cephalic nerves and the central nervous system. 

 Some of these seem to be true nervous elements although all may 

 not be. Most of the cells and groups of cells are clustered about 

 the cephalic portion of the nervous system. The numerous 



