KESPIRATOKY ORGANS IN ARANE^. 
69 
side of the base of each tracheal pedicel. In Segestria the 
ectodermal area of attachment is drawn out in a mediad 
direction in the form of a short, flat, unspined pouch (ec. t. 9, 
figs. 32 and 33), whicli opens into the short, smooth, flexible 
pedicel {ped.) connecting the rigid outer cuticula (cu.) with 
the spinous main trunk {tr.) of the trachea. This enta- 
pophysis is not respiratory, and the entire trachea is to be 
regarded as homologous only with the embryonic pulmonary 
Text-fig. S. Text-fig. 4. 
Segestriii senocnlata, ?. Argyroneta aquatica, $. 
Ventral surface of abdomen. — jmlm. sp., pulmonary spiracle; tr. sp., 
tracheal siiii-acle ; Ih, operculum of lung-books ; (j. o., genital opening ; 
Magn. 12. 
sac and its proliferation, as I have already stated in a previous 
communication (’95). That this must be the case may fairly 
be concluded from the position of the pair of spiracles (text- 
fig. 3) corresponding to the second pair in Tetrapneumonous 
spiders (text-fig. 2, p. ~)2) and from the position of the enta- 
pophysis on its medial side. Lamy (:02) has also expressed 
himself in agreement with this view, which differs entirely 
from that of Bertkau (’72), who considered the short posterior 
