THE DEVELOPMENT OF ADMETUS PDMILTO. 629 



EXPLANATION OF PLATES 82 & 33, 



Illustratiug Mr. L. H. Gougli's paper on ''The Development 

 oEAdmetus pumilio: a Contribution to the Em- 

 bryology of the Pedipalps." 



[N.B. — It must be borne in mind that the descriptions in tlie text are made 

 from whole series of sections, but tliat the drawings were eacii made from 

 one cut only.] 



PLATE 32. 



Figs. 1 and 1 a. — Embryo of Stage V ; explanations in tlie text. Magnified 

 12 times. 



Fig. 2. — Tlcconstruction of brain of embryo of Stage V. The parallel lines 

 are to demonstrate the position of the cavity caused by the alimentary canal, 

 otherwise as in text. Magnified 18 times. 



Fig. 3. — Sagittal section of lateral organ of embryo of Stage IV. Magnified 

 165 times, c. Cuticle, d. Deposit, e. w. External wall, i. tv. Internal 

 wall. p. Partition, o. c. Outer cavity, i. c. Inner cavity, i/. Yolk. 



Fig. 4. — Sagittal section of part of the abdomen of embryo of Stage V, 

 with genital cells. Magnified 220 times, v. Vacuole of germ-cell. mn. 

 Micronncleus of germ-cell. n. Nucleus of germ-cell. c. p. Cell-plasm of 

 germ-cell. a.e. Fifth abdominal extremity, c. Remains of coclom. 



Fig. 5. — Sagittal section of a portion of the heart of embryo of Stage V. 

 Magnified 330 times, io. Walls of heart, b.c. Blood-cells. i/. Yolk. e. 

 Epidermis. 



Fig. 6. — Sagittal section through cephalolhorax of embryo of Stage V. 

 Magnified 00 times. e.g. Coxal gland, o. c. g. Opening of coxal gland. 

 d. V. m. Dorso-ventral muscles, a. b. Accessory brain. 6. Brain. 



Fig. 7. — Horizontal section of rectum and mid-gut of embryo of Stage V. 

 Magnified 220 times, e. Epidermis, re. Rectum, en. Entoderm cells 

 forming mid-gut. m. Muscles forming sphincter and dilators, y. Yolk. 



PLATE 33. 



Fig. 8. — Sagittal section through embryo of Stage IV, showing Aulage of 

 part of ventral ganglion cord, and development of ganglia out of small sense- 

 orgau-like structures. Magnified 280 times, s. Surface pit. iu. Tube. 



