STRUCTURE AND ECONOMY OF SPIDERS. 325 
dark-brown colour, and have their pointed extremity 
directed towards the inner margin of the maxille, 
are fewer in number, enlarged at the extremity, and ° 
much longer and more distinct near the posterior end 
of each group than the closely compacted: ones that 
form its anterior part. These spines, by their figure- 
and arrangement, present a highly interesting subject 
for inspection under the microscope. 
From the foregoing observations it is evident that 
much careful investigation is yet required to complete 
our knowledge of the various minute appendages con- 
nected with the external organs of Spiders and of the 
purposes to which they are subservient. 
In attempting to drown a small Spider named 
Neriéne longipalpis, for. the purpose of taking its 
dimensions accurately by measurement, I was asto- 
uished to find that at the expiration of two days, 
though it had remained under water the whole of the 
time, it was as lively and vigorous as ever. This 
extraordinary circumstance induced me to submerge 
numerous specimens, of both sexes, in cold water 
contained in a glass vessel with perpendicular. sides, 
on the 21st of October, 1832, in which situation some 
of them continued for many days without having their 
vital energies suspended. 
This experiment I have tried with other minute 
species, and several of them have preserved an active 
state of existence for six, nine, and fourteen days, 
spinning their lines and exercising their functions as 
