JOURNAL OF MICROSCOPICAL SCIENCE. 
EXPLANATION OF PLATES XIX, XX, AND XXI, 
Illustrating Mr. F. M. Balfour’s Notes on the Develop- 
ment of the Araneina. 
PLATE XIX. 
Complete List of Reference Letters. 
ch. g. Ganglion of chelicerse. c. 1. Caudal lobe. ch. Chelicerse. pd. 
Pedipalpi. pr. 1. Praeoral lobe. pp^. pp^. etc. Provisional appendages. 
p. c. Primitive cumulus, sp. Spinnerets, st. Stomodaeum. 
I — IV. Ambulatory appendages. 1 — 16. Postoral segments. 
Fig. 1. — Ovum, with primitive cumulus and streak proceeding from it* 
Fig. 2. — Somewhat later stage, in which the primitive cumulus is still 
visible. Near the opposite end of the blastoderm is a white area, which is 
probably the rudiment of the procephalic lobe. 
Fig. 2»a and 2»b. — View of an embryo from the ventral surface and from 
the side when six segments have become established. 
Fig. 4. — View of an embryo, ideally unrolled, when the first rudi- 
ments of the appendages become visible. 
Fig. 5. — Embryo ideally unrolled at the stage when all the appendages 
have become established. 
Fig. 6. — Somewhat older stage, when the limbs begin to be jointed. 
Viewed from the side. 
Fig. 7. — Later stage, viewed from the side. 
Fig. la. — Same embryo as fig. 7, ideally unrolled. 
Fig. 8(2 and 85. — View from the ventral surface and from the side of 
an embryo, after the ventral flexure has considerably advanced. 
Fig. 9. — Somewhat older embryo, viewed from the ventral surface. 
PLATES XX AND XXI. 
Complete List of Reference Letters. 
ao. Aorta. «5. Abdominal nerve cord. cA Chelicerae. ch. g. Gan- 
glion of cheliceraj. ep. Epiblast. ht. Heart, hs. Hemispherical lobe 
of supra-oESophageal ganglion. 1. 1. Lower lip. m. Muscles, me. Meso- 
blast. mes. Mesenteron. mp.g. Malpighian tube. ms. Mesoblastic 
somite, oe. (Esophagus, p. c. Pericardium, pr. Proctodaeum (rectum). 
pd. Pedipalpi. pd. g. Ganglion of pedipalpi. pr. c. Primitive cumulus. 
s. Septum in abdomen, so. Somatopleure. sp. Splanchnopleure. st. 
Stomodseum. su. Suctorial apparatus, su. g. Supra-oesophageal ganglion. 
th. g. Thoracic ganglion, v. g. Ventral nerve cord. gk. Yolk. g. c. 
Cells derived from yolk. g. n. Nuclei of yolk cells. 
I g — IV g. Ganglia of ambulatory limbs. 1 — 16. Postoral segments. 
