268 FIELD. [Vol. XI. 



EXPLANATION OF PLATE XVI. 



Fig. 13. " Yellow cells " from testis of Dorocidaris papillaia. A, fresh, liv- 

 ing. B, stained with methyl green. C, stained with dahlia. 



Fig. 14. Spermatozoon. y4i-/^r;a.f ^/a«'a/zj', sea-water + dahlia ; sea-water + 

 methyl green. 



Fig. 15. Spermatozoon. Asterias glacialis, dilute tincture of iodine in sea- 

 water. 



Fig. 16. Spermatozoon oi Asterias glacialis. Flemming (strong formula) 24 

 hours : water 24 hours, dahlia, methyl green, glycerine. 



Fig. 17. Spermatozoon of Astei'ias glacialis. Flemming (strong formula) 24 

 hours : water 24 hours, safranin 1 5 minutes. 



Fig. 18. Spermatozoon of Asterias glacialis. Flemming (strong formula) 24 

 hours : water 24 hours, Delafield's haematoxylin. 



Fig. 19. Spermatozoon of Asterias glacialis. Flemming (strong formula) 

 gentian violet (24 hours); acid absolute alcohol: eosin in abs. alcohol 3 minutes, 

 clove oil. 



Fig. 20. Spermatozoon of Astropecten pentacanthtis. Very dilute acetic + 

 dahlia ; after 5 minutes. The centrosome and mitosome swell slightly. 



Fig. 21. Spermatozoon of Astropecten pentacaiithiis. Osmic vapor; dahlia; 

 glycerine. 



Fig. 22. Spermatozoon of Chaetaster longipes. Acetic 3%; methyl green + 

 dahlia. The centrosome has separated from the depression in the wall of the 

 nucleus, and has become entirely free from the spermatozoon. 



Fig. 23. Spermatozoon of Chaetaster longipes. Acetic 33%; methyl green. 

 A great distortion of the centrosome and mitosome results. 



Fig. 24. Spermatozoon of Strongyloccntrotiis lividus. Chloride of manganese 

 10% + dahlia. 



Fig. 25. Spermatozoon oi Echinocardium cordatum. Dilute gentian violet in 

 sea-water. 



Fig. 26. Spermatozoon of Echinocardiitm cordatum. Chloride of manganese 

 10% -f- dahlia. The normal shape of the nucleus is somewhat altered by the 

 reagent. 



Fig. 27. Spermatozoon of Ophiothrix fragilis. After 25 minutes in sea-water 

 + dahlia. 



Fig. 28. Spermatozoon of Ophiothrix fragilis. After one hour in sea-water 

 + dahlia. The nucleus has swollen considerably. 



Fig. 29. Spermatogone : Stichopus regalis. (Note. — Figs. 29 to 34 upon 

 treatment with Flemming (24 hours); water (24 hours); methyl green and dahlia; 

 glycerine.) The nucleolus has disappeared. The nuclear membrane still persists. 

 Two centrosomes are present. 



Fig. 30. Spermatocyte : Stichop7is regalis. 



Fig. 31. Spermatocyte: Stichoptis regalis. In mitosis; all of the chromo- 

 somes are not shown in the drawing. (Note. — The line from cy should go to 

 the spindle. No nuclear membrane present.) 



Fig. 32. Spermatocyte : Stichopus regalis. After division of the nuclei to 

 form two spermatids. The cytomicrosomes (cy') which formed the spindle, previ- 

 ously inside the nucleus, are now in the cytoplasm. (Note. — In the upper cell 

 the letters, c and w, should be reversed.) 



