232 PROCEEDINQS OP THE ACADEMY OF [1886. 



this evening. The specimens are all imperfect, showing only 

 the abdomen and a part of the cephalothorax. The most of tliem 

 were compressed vertically and give a transverse view. Tlie 

 compressed abdomen reminds one of the pygidium of a trilobite, 

 hence the specific name. A single specimen compressed laterally 

 shows well the elevated and rounded abdomen characteristic of 

 our modern spiders. The cephalothorax is minutely punctate. 

 The species is interesting as occurring at the base of the coal 

 measures. The locality is no longer worked and the species may 

 be considered scarce. 



Messrs. Calvin McCormick and Samuel Wagner were elected 

 members. 



The following was ordered to be printed : 



