402 PROCEEDINGS OF THE ACADEMY OF Play, 



appeared as illustrated in the pedipalps. This is further exemplified 

 with the araneads in which one never finds isolated slits on the dorsal 

 side of the abdomen and none on the dorsal side of the cephalothorax 

 except a few that still persist on the cephalothoracic shield. In some 

 species among the araneads the single slits seem to be as numerous as 

 ever, but in all cases they have become more or less regularly distri- 

 buted. Where the single slits are as numerous as ever, then the 

 compound and simple organs must be entirely new formations. 



Among the lower orders the range* is from a total absence of either 

 isolated slits or organs for the entire animal to many single slits plus 

 two compound organs for each leg. Among the aranea* the range is 

 from 41 c. o., 12 s. o., 82 s. s. to 69 c. o., 2 s. o., 64 s. s. The total 

 number of slits in all these organs plus the scattered ones of the latter 

 aranead is probably twice that of the former. According to this the 

 development of the lyriform organs in the latter is twice that of the 

 former, while in the lower orders this ratio is doubled many times. 



II. PHYSIOLOGY. 



4- Experiments. 

 (a) Olfactory Sense. ^ 



Triangular experimental cases were constructed by using three 

 pieces of glass, two of which were 10 cm. wide by 13 cm. long and the 

 other 6 cm. wide by 10 cm. long. Cheese cloth served as a bottom. 

 The glass and cheese cloth were held together with adhesive tape. 

 A top of cardboard was laid over each case to prevent the escape of the 

 specimen. Cases of the same dimensions except height were used 

 for the attiids. These were only one centimetre high with a glass top. 

 The extreme ends of the experimental cases rested on two supports 

 which were placed on sawdust, the latter being used to break the jar 

 caused by heavy walking. A screen was placed in front of the cases 

 to prevent the spiders from seeing the observer. 



( )n account of their size, abundance, and because their webs did 

 not interfere with the experiments Lycosa lepida, L. scutulata, and 

 Phidippus purpuratus were employed. However in one test Pardosa 

 lapidicina Emert. was used. In all cases the spiders were brought 

 immediately fresh from the fields, then and each day afterwards they 

 were fed and watered. They were experimented with in series of 

 fourteen in which each specimen was tested each day with five or six 

 different odors for four or five days. The first experiments were made 

 with the following five oils; clove, thyme, wintergreen, peppermint 

 and bergamot, each of which was kept securely in a small vial. The 



