EXPLANATION OF PLATE 53. 



Fig. 39. Side view of same embryo. 



Figs. 40 — 42. Drawings liy Professor Balfour of three transverse sections tiirough 

 the embryo from wliich fig. 36 was talien. (Zeiss c, Camera.) Figs. 40 and 42 pass 

 through the region of the blastopore. 



hi. Blastopore, ep. Epiblast. hy. Hypoblast, me. Mesenteron. mcs. Meso- 

 blastic somite. 



Fig. 43. Male generative organs of PeHpatus capcnsis, viewed from the dorsal 

 surface. (From a drawing by Miss Balfour.) 



a.g. Enlarged crural glands of last pair of legs. F. 16, 17. Last pairs of legs. 

 /. -Small accessory glandular tubes. /. Common duct into which vasa deferentia 

 open. i>. r. Prostate, te. Testes, v. c. Nerve-cord. v. d. Vas deferens. 



