86o 



THE AMERICAN .XATURAL/ST. [\'0L. XXXVIII. 



McCook ('90) concludes that the senses of smell and hearing 

 are very rudimentary and are distributed over the entire body. 

 They are located in the delicate hairs which constitute the cov- 

 ering; and armature, so that the nervous system receives through 

 these organs or appendages impressions that may be considered 

 analogous to hearing and smell in the higher animals. Further, 

 the sense of hearing can scarcely be distinguished from that of 

 touch as it is known to us. He thinks that even in the orb- 

 weavers there is no true sense of hearing, but that the web fila- 

 ments transmit the vibrations and the sensation is tactile rather 

 than auditory. 



Pocock ('93) found spiders sensitive to heat, provided with 

 acute sense of taste, with defective sight and no hearing what- 

 ever. 



Dahl (:o4) designates the auditory hairs as trichobothria and 

 makes an elaborate classification of suborders according to their 

 distribution. 



The two species used by me for experiment are Gcolycosa 

 texana Montg. and Pardosa mcrcurialis Montg. and are found 

 in great abundance in Austin, Texas, and its vicinity. The 

 large Geolycosa texana lives in underground holes of I to U 

 inches in diameter and digs its home on creek banks or in the 

 fielda wherever the ground is comparatively clear except for a 

 close sod of native grass. Pardosa mcrcunalis has been found 

 mainl>- under small surface stones along the banks of streams 

 or in the dry beds during droughts, but sometimes occurs in 

 great abundance far from water. 



The specimens used for the observations were kept in cages 

 niade by fastening glass plates together at their edges with 

 gummed linen, as described by Montgomerv (: 03). 



The apparatus 



■ these experiments were tuning torKS 

 tl 5 1 2 \ ibrations and a speciall)' pr^"- 

 e cage was made of three glass plates 

 inen and covered with black paper, 



