694 NOTES ON THE DEVELOPMENT OF THE AKANETNA. 



EXPLANATION OF PLATES 30, 31, AND 32. 



PLATE 30. 



COMPLETE LIST OF REFERENCE LETTERS. 



ch. Chelicerse. ch. g. Ganglion of chelicera?. c. 1. Caudal lobe. p. c. Primitive 

 cumulus, pd. Pedipalpi. pr. I. Prreoral lobe. . pp 1 . // 2 . etc. Provisional ap- 

 pendages, sp. Spinnerets, st. Stomodreum. 



I IV. Ambulatory appendages, i 16. Postoral segments. 



Fig. i. 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. 3 and 3$. 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 rudiments 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. "ja. Same embryo as fig, 7, ideally unrolled. 



Figs. 8 and 8/'. 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 31 AND 32. 



COMPLETE LIST OF REFERENCE LETTERS. 



ao. Aorta, ab. g. Abdominal nerve cord. ch. Cheliceraj. ch. g. Ganglion of 

 chelicerae. ep. Epiblast. hs. Hemispherical lobe of supra-cesophageal ganglion. 

 ///.Heart. //. Lower lip. m. Muscles, me. Mesoblast. mes. Mesenteron. mp.g. 

 Malpighian tube. ms. Mesoblastic somite, cc. (Esophagus. /. c. Pericardium. 

 pd. Pedipalpi. pd. g. Ganglion of pedipalpi. pr. Proctodxum (rectum), pr. c. 

 Primitive cumulus, s. Septum in abdomen. st>. Somatopleure. sp. Splanchnopleure. 



