10 
W. F. PURCELL. 
According to her tlie invagination -which forms the pulmonary 
sac is situated ou the anterior edge of the lateral part of 
the base of an abdominal appendage and is apparently uncon- 
nected with the latter (p. 177). 
Development of the tracheae in Araneae. — Schimkewitsch (’87) 
states that the tracheae in Lycosa saccata arise by invasri- 
nations of the ectoderm. In his Russian paper (’86a) he 
gives a figure of a. developing trachea [ect, fig. 29 a), without, 
however, recognising it as such. 
Kishinouye (’90) observed an ectodermal invagination in 
various spiders in the basal part of the second abdominal 
appendage on the interior side. This invagination forms a 
deep tube at the time of hatching and the author calls it an 
“ abortive trachea.” 
Simmons (’94) found the same invagination in Agelena 
nmvia and Theridion tepidarior um, and in addition 
what he considers to be aborted lung-leaves. 
Finally, in my abstract (’95) of the present paper the origin 
of the greater part of the tracheae in Attus floricola from 
ectodermal tendons is stated in outline. 
TV. Thtk Provisional Abdominal Appendages in the Embryo 
OK Attus Floricola. 
The description begins with the stage^ immediately 
preceding the apnearance of the pulmonar}’- folds 
(stage 1, F)t. 1). 'Phe embryonic band has attained its 
o-reatest length, and the process known as the reversion 
is about to commence. A sagittal section (PI. 1, fig. 4) 
through the abdominal region shows eight abdominal 
segments with coelomic sacs. The first abdominal (seventh 
post-oral) segment bears no appendages in this species, but 
the following four (eighth to eleventh post-oral) are each 
provided in their posterior region with a low, flat-topped, 
' CoiTespondiny to the stage in Korsclielt and Heider. p. 581. fig. 
and to Locy’s PL ii, fig. 8, and Balfour's fig. fi. A list of the v.irious 
stages and of the figures referring to each is given in the explanation of 
tlie plates. 
