KESriEATORY ORGANS IN ARANE^. 
109 
Segestria senociilata (ad. $ ). Obliqiiely transverse section cut at 
an angle of 38° to the horizontal (of. fig. 33) though the hasal part of a 
traclieal trunk {combined from a couple of sections). 
Fig. 33. — Similar to the last but a sagittal section, showing the 
entapophysis cut across the line indicated in fig. 32. 
Fig. 34. — (Zeiss oil iui., IV, Flemmings sol.) Embryo of Tege- 
naria atrica, just after hatching. Transverse section through two 
upper pulmonary saccules. 
PLATE 7. 
Figs. 35 and 35a. — (Zeiss oil im., II, hot ale. subl.) Embryo of 
Attus floricola at the stage with five pulmonary furrows (from the 
same series of sections as figs. I6-1()E). Longitudinal sections through 
the tracheal appendage along the lines indicated in fig. 27. 
Fig. 36. — (Zeiss jV oil im., I.) Crypsidromus intermedins. 
Sagittal section through the rudimentary entapophysis or muscular 
stigma of the first pulmonary sternite, showing the distal j^ai’t of some 
of tlie long hypodermal filn-es (hij.') to which the entochondrite of the 
pulmonary segment is attached. 
Figs. 37 and 37a. — (Zeiss j'.j oil im., I, ale.) Palpimanus sp. 
Transverse sections through the anterior (fig. 37) and tlie pf)sterior 
(fig. 37a) regions of the median entapophysis of the tracheal system. 
Fig. 38. — (Zeiss C, IV, caustic potash.) Scytodes testudo. 
Basal part of chitiuous skeleton of tlie tracheal system. 
Fig. 39. — (Zeiss oil im., IV, ale.) Scytodes testudo. Trans- 
verse section through the ciiticular lining of the median entapophysis 
of the tracheal system along the line indicated in fig. 38. 
Fig. 40. — (Zeiss oil im., I.) Harpactes Hombergi (ad. (^). 
Median sagittal section through the cuticula of the iuterpulmonary fold 
and the genital opening. 
Fig. 41.— (Zeiss 0, II, hot ale. subl.) Embryo of Attus floricola 
after the reversion in sagittal section, showing the principal muscles, 
ectodermal and mesodermal tendons and segmentation of the alidomen 
(combined from several sections). The lungs, genital cords, and the 
stercoral pocket (imagined as seen from the medial side) are di-awn in 
to show their toi)ography, the last being represented in median section. 
The muscle (p. ob. m. 8) is the only one lying between the genital duct 
(fj.) and the lung-books (lb.). 
Fig. 42. — (Zeiss A, II, caustic potash.) Tegenaria domestica 
(adult). Portions of the pair of median tracheal trunks, showing the 
