1911.] NATURAL SCIENCES OF PHILADELPHIA. 401 



organ composed of five slits is found on the second joint of each species. 

 Chelicera and maxilla? with only a few, both ventral and dorsal sides 

 of the abdomen and dorsal side of the cephalothorax with many small 

 scattered slits. 



Hansen and Sorensen stated that it was impossible to find lyriform 

 organs in the order Ricinulei. 



Concerning the Phalangids Hansen says that numerous isolated 

 slits of unequal lengths occur on the first three joints of the legs, third 

 joint of the palps, chelicera, ventral side of the abdomen, but only a 

 few on the cephalothorax and dorsal side of abdomen. 



Gaubert was unable to find any lyriform organs in the order of 

 Acarina. Hansen thought that he found some scattered, very tiny 

 slits on the shield and a most remarkable transverse slit on the legs 

 of one species. Thus he thinks that they appear as single slits in this 

 family. 



To briefly summarize the discussions about the disposition of the- 

 lyriform organs in all the orders of arachnids, we see that scorpions 

 possess many irregularly scattered slits of various sizes on the legs 

 and palps, but no compound organs. For the family. Thelyphonicke, 

 of the pedipalps there are many scattered slits on all the appendages, 

 a few on both sides of the cephalothorax, while many are scattered all 

 over the abdomen. In this family there is only one compound organ 

 on each leg, while in the family, Phrynidae, there are two compound 

 organs on each leg besides the many slits. For the solifugids the 

 only signs of lyriform organs are a few scattered slits on the chelicera. 

 The pseudoscorpions have only one organ of five slits on each leg and 

 scattered slits occur everywhere. The phalangids have only numerous 

 slits scattered everywhere; the acarinids have nothing more than a 

 few scattered slits, and no slits have ever been found in the Palpigradi 

 and Ricinulei. 



(//) Phytogeny. 



Thus it is clear that the development of the lyriform organs in all 

 the orders except Aranea 1 is in a very primitive state. In the degree 

 of development perhaps the pedipalps stand next to the araneads for 

 some of them have two compound organs on each leg, while Palpi- 

 gradi and Ricinulei have these structures totally absent. It seems 

 probable that at one time all kinds of lyriform organs were nothing 

 more than minute slits irregularly scattered over all parts of the entire 

 body as seen in some of the lower orders. Then when organs, made 

 their appearance the tiny slits on the dorsal side of the body dis- 



