12 PROCEEDtXGS OF THE 



I'ith Fehrucmj, 1875. — Subject, " Geology." Numerous oolitic 

 and cretaceous fossils were exhibited ; also mammalian remains from 

 the crag, and Erith tertiaries, as well as rare and curious minerals — 

 different forms of silver, tin, iron, arsenic, antimony and galena; and 

 in answer to inquiries, Mr. S. Webb explained the different clays of 

 the neighbourhood, and gave a short account of the different theories 

 as to the deposit of flint. 



12«/t March, 1875. — The President exhibited a number of speci- 

 mens belonging to the class Arachnida, whjph comprises the Spiders, 

 Scorpions, Ticks, Mites and other allied tribes, and afterwards ad- 

 verted to some of the habits of the Spiders proper, whose classification 

 is principally founded upon the number and position of their eyes. 

 He also called attention to the construction of the nests of the Trap- 

 door Spiders {Cteniza and Nemesia), some of which, as described by 

 the late Mr. Moggridge, have branched tubes furnished with a lower 

 lateral door at the point of intersection, calculated to delude an 

 enemy in pursuit along the empty branch. He stated that he had 

 met with some having a similar trap-door at the bottom of the tube 

 as well as one at the top, which condition could be artificially 

 produced by reversing one of the nests in a flower-pot and breaking 

 off the lower end, now uppermost, when the spider would construct 

 a new trap-door to close the orifice. The President has described 

 this species under the name of Mygale {Cteniza) lonica. The 

 noctui-nal habits of C. ariana, one of these spiders, have been 

 observed in the island of Teuos : they come out of their nests, fasten 

 their open trap-door to some adjacent object, and spin a web about 

 six inches long and scarcely half an inch in height, for the purpose of 

 intercepting their prey, which webs are removed before morning, 

 when the trap-doors are closed. This species, as well as lonica, are 

 now comprised in a new genus, which Professor Ausserer, of Vienna, 

 has denominated Cijrtocarena. 



The tentnest of another spider, the Clotho Durandii of Latreille 

 (or Uroctea quinquemaculata of Dufour) was shown, presenting several 

 angular projections whereby it is attached to a rock or block of stone, 



