TiESPIKATOKY ORGANS TN ARAXEiE. 
105 
Point at wliich the entochonclrite is attaclied to the liy]^)odennis. 
y. Thvee-celled column, z. Pavement cell. w'. x' x' . if and y'. z' . 
Anterior, distal, and jjosterior sides of apjDcndage. 
PLATE 1. 
Embryology of Attns f lor i col a. 
[Longitudinal sections are cnt piirallel to the principal axis (pr. ax. in 
figs. 1-3) of the appendage and at i-ight angles to the posterior margin 
of the latter. Transverse sections are parallel to the principal axis and 
to the posterior margin.] 
Figs. 1-3. — (Zeiss oh]. C, oc. I, hot ale. snbl.) Transverse sections 
showing the change of position of the first pair of abdominal appendages 
during the reversion of the embryo. Fig. 1 I'e^n’esents the stage with 
two pnlmonary furrows, fig. 2 witli three, and fig. 3 with four, five, or 
more furrows. 
Fig. 1. — (Zeiss C, 111, hot ale. snbl.) Longitudinal section tlirough 
tlie lateral region of the four abdominal appendages, just ju'evious to 
the appearance of the pulmonary furrows and the commencement of 
the reversion. 
Figs. 5 and oa. — (Zeiss C. III. Iiot ale. snbl.) Longitudinal sections 
through the abdominal api^endages at tlie stage with two indmonary 
furrows (/. 1,/. 2), con-esponding to fig. 1. Fig. o glasses tlu-ough the 
medial, fig. 5 a through the lateral region of the anterior appendages. 
Figs. () and ()A. — (Zeiss C, III, hot ale. snbl.) Longitudinal sections 
through the abdominal appendages at the stage with five or six pul- 
monary fuiTows, corresponding to fig. 3. Fig. (i passes through the 
medial, fig. (>A through the lateral region of the appendages. 
Figs. 7 and Ta. — (Zeiss oil im.. II. hot ale. subl.) Longitudinal 
sections through the medial (fig. 7) and lateral paid (fig. 7 a) of the first 
abdominal appendage (enlarged from the same embryo as fig. I) just 
before the formation of the pulmonary furrows; cp., epitlielium (belong- 
ing to somite 9) behind first appendage. 
PLATE 2. 
Embryology of Attns floricola. 
[Longitudinal sections are cut parallel to the principal axis (pr. ax. 
in fig. 1) of the appendage.] 
Fig. 8. — Diagrammatic view of the posterior side of the first abdo- 
minal appendage at the end of the stage (con-esponding to fig. I with 
two pulmonary fuiTOws,/. !,/• -) (from a wax reconstruction). The 
parallel lines represent the planes of sections; ep., the ejiitheliuni 
