THE SKNSKS AND TIIKIK OIK1ANS. 



299 



The 



Sense of 

 Smell. 



to what extent V And, in the second place, where are the olfactory organs 

 located V The conclusion which I had reached, as the result of experi- 

 ments and observations of my own, is that spiders have little 

 sense of smell, although they are in some way affected by certain 

 odors. I have long entertained the opinion that the sense of 

 smell in spiders, like that of hearing, abides entirely in the deli- 

 cate hairs which constitute the covering and armature of the creature. I 

 have thought that in some way the nervous system receives through these 

 organs or appendages impressions that may be considered analogous to 

 hearing and smelling in the higher animals; but, further, that both these 

 senses are in an extremely rudimentary condition. 



These conclusions are substantially confirmed by the experiments re- 

 corded by Professor and Mrs. Peckham, which were carefully performed 

 and continued through a number of examples large enough to 



eck ~ justify a conclusion. Their method was to place a rod dipped 

 hams' Ex-. . ,. , ., . , , . , ,. 



- ts ln vanous essential oils, cologne, and several kinds or perfumes, 



close to the various parts of the spiders, and note the effect. 

 The results were carefully tested in all cases by first presenting a clean rod. 

 Among the essential oils used were oil of peppermint, of lavender, of cedar, 

 of cloves, and of wintergreen. The first experiments made were upon some 

 tame Attida; that had taken up their abode with them. These were fear- 

 less little creatures, ready to jump upon the finger, catch the gnats that 

 were offered them, or drink from a spoon. They showed the same facility 



in smelling that they exhibited in seeing, and were quick to re- 

 o ' spond to any test of their sense of smell. The most common 



effect produced by an odor was that it ca'used the spiders to raise 

 their fore legs and palps, which sometimes they dlso moved up and down. 

 In one case great excitement was caused by the approximation of pepper- 

 mint. In several cases the spiders, after indicating that they noticed the 

 scent, moved away from it. 



With Orbweavers the effect of the various perfumes was to cause an 

 upward jerk of the abdomen and a movement of the legs. Sometimes the 

 tips of the legs were rubbed between the palps and the falces. The result 

 of two hundred and twenty experiments may be summed up as follows : 

 Three species, Epeira hortorum, Doloinedes tenebrosus, Herpyllus ecclesias- 

 ticus, did not respond to the test. In all other cases it was evident that 

 the scent was perceived by the spiders, although it may be noted that 

 among spiders of the same species great differences of degree exist in their 

 sensitiveness to odors. The spiders exhibited their sensitiveness to the 

 various perfumes by movements of the legs, palps, and abdomen; by shak- 

 ing their webs ; by running away ; by seizing the rod which had been 

 dipped into the scent, enswathing it as they would insects ; in the case of 

 the Attidse, by approaching the testing rod with the first leg and palps 

 held erect, but whether in the way of attacking it, or, as it sometimes 



