RBSriilATOKY ()K(;ANS IX ARANEA'l. 
107 
PLATE 4. 
Embryology of Attus floricola. 
[Longitudinal sections are cut parallel to tbe principal axis (pr. ax. 
in fig. 3) of the appendage.] 
Fig. 16. — Diagrammatic view of the posterior side of first abdominal 
appendage at the stage with five well- developed pulmonary fim-ows 
(corresponding to fig. 3) from a wax reconstruction. The parallel lines 
represent the planes of section ; ep., the epithelium represented as cut 
along the line marked (ep., fig. 16) in figs. 16a-16d. 
Figs. 16a-16e. — (Zeiss oil ii>i-> H- bot ale. subl.) Longitudinal 
sections through the first abdominal appendage, of which fig. 16 is a 
reconstruction. 
Fig. 17. — (Zeiss oil im., 11, liot ale. subl.) Transverse section 
tlirough first alidominal appendage shortly before tlie hatching of the 
emlnyo, cut along the line indicated in fig. 18. 
Fig. 18.— (Zeiss oil im., II, hot ale. sul)l.) Sagittal section of tlie 
same stage as fig. 17 and cut along the line indicated in the latter 
figure. 
PLATE 5. 
Fig. 19. — (Zeiss ^ oil im., I.) Sagittal sections through the cuticula 
of the lateial part of the inteipulmonary fold (between the entapo- 
pliysis and the lung-book), or its rudimentary remains in A, Lycosa 
sj). ; B, Philodromus fuscomarginatus (subadult) ; and C, Argy- 
roneta aquatica (adult ). The sections are all arranged in the same 
positions. 
Fig. 29. — (Caustic potash.) Attus sp. (adult). Chitinous skele- 
ton of abdomen anterior to the pulmonary spiracles, drawn from 
behind. The posterior wall of the ante-chamber has been removed on 
the right side, and on the left the grate-like openings are visible through 
this wall. 
Fig. 21. — (Caustic potash.) Tegenaria domestica (ad. $ ). 
Chitinous skeleton of abdomen from above. 
Fig. 22. — (Zeiss oil im., I, picro-sulphuric acid.) Attus floricola 
(mature, or nearly mature $ ). Sagittal section through the inter- 
p\ilmonary fold between the lung-book and the entapophysis, showing 
the cuticula only. 
Fig. 23. — (Zeiss oil im., I, Flemming's sol.) Attus floricola 
(ad. (5*). Sagittal section through the interpulmonary fold and the 
entapophysis in the region indicated in fig. 20. 
