754 PROCEEDINGS OF THE ACADEMY OF [Oct., 



tissue so peculiar to the Gordiacea, the ''parenchym," and its arrange- 

 ment into layers. Not until that is done can the structure of the adult 

 be adequately interpreted. 



Literature List. 



Camerano, L. 1889. I primi momenti della evoluzione clei Gordii. Mem. 



Real. Accad. Sci. Torino, XL. 

 Idem. 1892. Ricerche intorno al parasitismo ed alio sviluppo del Gordius 



pustulosus. Atti Accad. Sci. Torino. 

 Grube. 1849. IJeber einige Anguillulen und die Entwickelung von Gordius 



aquaticus. Arch. Naturg., 29. 

 Hautmann, M. 1902. Studien am thierischen Ei. 1 Ovarialei und Eireifung 



von Asterias glacialis. Zool. Jahrb., 15. 

 Leidy, J. 1850. Notes on the Development of the Gordius aquaticus. Proc. 



Acad. Nat. Sci. Phila. 

 Idem. 1870. The Gordius or Hairworm. Aiuer. Entoni. and Bot., 2. 

 LiNSTOW, O. V. 1890. Ueber die Entwickelungsgeschichte und die Anatomic 



von Gordius tolosanus. Arch. mikr. Anat., 3-4. 

 Idem. 1891. Weitere Beobachtungen an Gordius tolosanus und ]NIermis. 



Ibid., 37. 

 Meissner. 1856. Beitrage zur Anatomie und Phj'siologie der Gordiaceen. 



Zeit. ^viss. Zool., 3. 

 Montgomery, T. H., Jr. 1898. Comparative Cj'tological Studies with Especial 



Regard to the Morphology of the Nucleolus. Joiirn. Morph., 15. 

 Idem. 1903. The Adult Organization of Paragordius varius (Leidy). Zool. 



Jahrb., 18. 

 Tretiakow, D. 1901. Trav. Soc. Imp. Natural. St. Petersbourg, 32. 

 Vejdovsky, F. 1894. Organogenie der Gordiiden. Zeit. tviss. Zool., 57. 

 ViLLOT, A. 1874. Monographie des Dragonweaux. Arch. Zool. Exper., 3. 

 Idem. 1891. L'Evolution des Gordiens. Ann. Sci. Nat., Zool. 



Explanation of Plates XLIX and L. 



The following abbreviations have been emploj^ed in the figures : 



BL, blastopore. 



Cut., cuticula. 



Di., diaphragm. 



Fib., fibre cells. 



Gl, gland. 



Gl.d., gland duct. 



Glo., globules within intestine. 



H., cuticular hooks. 



Ily., hypodermis. 



In., intestine. 



Mes., mesenchjmi cells. 



Mus., musculature. 



Nv., nervous thickening of hypodermis. 



Sp. 1-Sp. 3, spicules of rows 1-3. 



St.d., dorsal stilets. 



St. v., ventral stilet. 



All the figures, except 33-35, are camera lucida drawings at a magnification 

 of 1312 diameters. 



Plate XLIX, Fig. 1. — Ovocyte from lateral diverticulum of ovary, at end of the 



growth period; the yolk globules shaded. 

 Figs. 2-5. — Nuclei in successive prophases preceding the formation of the 



first polar body. 

 Fig. 6. — Portion of an egg near the proximal end of the cloaca, showing the 



first polar spindle and the entering spermatozoon. 

 Fig. 7. — Pole view of the first polar spindle. 

 Fig. S. — Outline of the whole egg, from a posterior end of the cloaca, showing 



the two egg-membranes, first polar spindle and spermatozoon. 

 Fig. 9. — Portion of the periphery of an egg, showing first polar body formed. 

 Fig. 10. — Outline of egg, showing second polar spindle, sperm nucleus and, 



separated from the surface of the egg, the two membranes. 



