534 
W. F. PURCELI,. 
entocliondvite ^.9 is attached (in Segesti'ia at least) to a 
small lobe of the medial side of the tracheal pedicel. This 
lobe (the entapophysis of the tracheal segment), which I 
have already described and figured (:09, figs. 32 and 33, 
ee.f.9), is not really a part of the trachea proper, being merely 
connected with the base of the pedicel and unspined internally, 
and I am not even sure that it is present in Dysdera or 
Harpactes, in which genera the entochondrite may possibly 
be attached directly to the integument at the medial basal 
angle of the tracheal pedicel. From the position of the 
trachea on the lateral side of the entochondrite t.9, it is 
evident that the whole of the trachea must be considered as 
homologous with a pulmonary sac or lung-book, as I have 
already pointed out (’95) and Lamy also agrees with this view 
by reason of the position and appearance of the tracheae and 
the complete separation of the spiracles (:02, p. 259). 
Oonopidae. — This family is very closely allied to the Dy s- 
deridae as was pointed out by Bertkau (’78), who included 
Oonops in the latter. The only anatomical difference of any 
importance connected with the respiratory segments appears 
to be the presence of an intertracheal fold observed by Lamy 
(:02), joining the two tracheae in the Oonopida3. 
I found the muscular system connected with these seg- 
7uents to be practically identical in the two families, all the 
characteristic muscles of the Dysderidm being present in 
the Oonopid, Calculus bicolor, examined by me, although 
sometimes in a somewhat modified form.^ Thus the muscle 
29 (text-fig. 7) is much shorter and 15 (text-fig. 6) somewhat 
longer in the Oonopid, as the posterior trachefe ai-e here 
placed further back. Tlie lateral entochondrite t. is particu- 
larly conspicuous, much more so than in Segestria. 
The tracheal trunks are quite similar in both families. 
Those of Oonops were first described by Bertkau (’78) and 
later in greater detail by Lamy (:02), who also examined a 
* Three additional muscles not noticed in Segestria are given in 
figs. 1 and 2, hut two of these (ru. 38 and 40) are also found in the 
female of Harpactes (fig. 3). 
