Bennet Mills Allen 145 



EXPLANATION OF PLATES. 



All figures except No. 1, were outlined witti the aid of a camera lucida. 



al., albuginea. m. r., mesenteric ridge. 



c, blood corpuscle. nil., nucleus. 



c. B., capsule of Bowman. oc, oocyte. 



cen., centrosphere. p., peritoneum. 



c. P., cord of Pfliiger. p. s., primitive sex-cell. 



c. p., epithelial plate. r., rete. 



ev., evagination of capsule of r c, rete cord. 



Bowman. r. t., rete tubule. 



f. c, follicular capsule. s. c, sex cord, 



gr., glomerulus. st., stroma. 



ger., germinative cell. s. tu., seminiferous tubule. 



gr., granulosa cell. s. g., sex gland. 



i. c, interstitial cell. t., testis. 



m., mesonephros. t. r., tubulus rectus. 



m. f., mesenteric fundament. th. i., theca interna. 



m. p., membrana propria. th. e., theca externa. 



PLATE I. 



Fig. 1. Reconstruction of the anterior end of the left mesonephros. Pig 

 embryo, length 12.5 cm. 



Fig. 2. Fundament of the rete ridge. Pig embryo, length 0.7 cm. Trans- 

 verse section, x 893. 



Fig. 3a. Fundament of sex gland. Pig embryo, length 0.7 cm. Trans- 

 verse section, x §93. 



Fig. 3b. Same as 3a, showing primitive sex cell in portion of peritoneum. 

 X893. 



Fig. 4. Fundament of sex gland. Pig embryo, length 1.0 cm. Transverse 

 section, x 893. 



PLATE IL 



Fig. 5. Fundament of sex gland. Pig embryo, length 1.25 cm. Transverse 

 section, x ^08. 



Fig. 6. Fundament of rete. Pig embryo, length 1.4 cm. Transverse section. 

 X893. 



Fig. 7. Fundament of sex gland and mesentery. Pig embryo, length 1.4 cm. 

 Transverse section, x 893. 



PLATE in. 



Fig. 8. Fundament of sex gland (peripheral portion). Pig embryo, length 



1.6 cm. Transverse section, x 608. 



Fig. 9. Fundament of sex gland (peripheral portion). Pig embryo, length 



1.7 cm. Transverse section, x 893. 



Fig. 10. Medullary cord of ovary. Pig embryo, length 5 cm. x 893. 



