40 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
these differently formed glands prepare different secretions. However, the 
only difference which Meckel obtained by applying a few reagents was that 
the cylindrical glands became more coagulated through alcohol and acids 
than others. We may now enter upon a detailed description of these silk 
glands, for which I am particularly in- 
; debted to the admirable stud- 
Sica ies of Drs. Bucholz and Lan- 
mee dois,t and of Meckel.? In 
some measure, also, I have 
drawn upon the English microscopists, 
Messrs. Underhill and Meade. I have 
tried, however, to confirm all statements 
accepted by me by independent studies 
of our own fauna. 
The secretions of Epeira diademata 
on which spider most of the valuable 
studies here referred to have been made, 
are in not more than a thousand glands, 
which are connected with an equal num- 
ber of independent ducts. There are 
three different sorts of these glands, 
which are distributed to their own es- 
pecial spinnerets. Each spinneret possesses a large and somewhat variable 
number of small pyriform glands, and besides this one or more larger 
glands. Concerning these I have 
adopted substantially the conclu- 
sions of Bucholz and Landois, which 
are confirmatory, for the most part, 
of the principal statements of Meck- 
el, and which are almost wholly in 
accord with my own stud- 
ies as far as they have 
been prosecuted. The py- 
riform glands py.g, vastly exceed 
the other forms in number, as there 
are present In every spinneret one 
hundred or more. However, they 
may not exceed the less numerous 
but considerably larger gland forms in quantity of secretions. They are ar- 
ranged, as has already been said, in round clusters of about two millimetres 
Fic. 31. Pyriform glands, caudate; A. cophinaria. 
Pyriform 
Glands. 
Fic. 82. Pyriform glands of Argiope. 
1 Anatomische Untersuchungen iiber den Bau der Araneiden: yon Dr. Reinhold Bucholz 
und Dr. Leonard Landois. Archiy Anatomie, Phisiologie und Missch. Med. Jahrgang, 1868, 
page 240 sq. (Leipzig.) 
* Heinrich Meckel: Mikrographie einiger Driisen Apparate der niederen Thiere. Archiy 
f. Anat. Phys. (Berlin), 1846, page 1 sq., Pl. III. 
