496 H. F. MOORE. 



EXPLANATION OF PLATE XXVIL 



Fig. II. Longitudinal section through valvular fold Va. in Fig. 4. X400. 

 B.V., blood vessels. E., columnar lining cells of crop. G.^ gland cells. N., free (.?) 

 nuclei lying at bases of epithelial cells. M., muscle fibres derived from circular 

 layer of alimentary canal. 



Fig. 12. Longitudinal section of gizzard. X400. C, thickened cuticular lining. 

 E., epithelial layer secreting C. B.v., longitudinal blood vessel. C.v., circular 

 vessels between the bundles of the greatly hypertrophied circular muscle layer Cm. 

 L.m.f longitudinal layer of muscle. 



Fig. 13. Longitudinal vertical section of prostate. X 70. 14-16 and 15-16 septa. 

 P., layer of chitin-producing cells surrounding atrial cavity A. L.m., longitudinal 

 and Cm., circular, muscle layers of body wall. Hy., hypodermal layer. A few 

 sections external to this, the upper end of atrial chamber receives the sperm 

 duct. 



Fig. 14. Longitudinal vertical section of prostate, more lateral than Fig. 13, 

 and passing through external male pore. X 70. A., atrial cavity. ^, male pore 

 (atriapore). P., layer of chitin-producing cells. G., layer of granular gland cells. 

 The approximate distribution and the region in which these cells open is shown 

 by the cross-hatched area. S.d., sperm duct passing up the anterior wall of pros- 

 tate. 14-15, 15-16, 16-17 septa, L.m., longitudinal, and Cm., circular muscle 

 layers of body wall. Hy., hypodermis. 



Fig. 15. Section of prostate in the region P. of Fig. 13. X 210. Coe., coelomic 

 membrane. P., chitinogenous glands. N., necks of same, with chitinous spic- 

 ules, Ch., protruding from their mouths into atrial cavity. Mm., muscle fibres. 

 E., layer in which lie scattered columnar cells with oval nuclei. 



Fig. 16. Section of prostate through one of the regions G. in Fig. 14. X 210. 

 Coe., coelomic membrane. G., granular gland cells prolonged into slender necks, 

 N., parallel to one another. 



Fig. 17. Columnar cells lining atrial cavity in the narrow zone between the 

 orifices of cells of regions P. and G., Fig. 14. X750. 



Fig. 18. Enlarged section of region E. in Fig. 15. X750. Ch., chitinous fila- 

 ments, which in some cases may be traced into the necks, N., of the chitinogenous 

 gland cells. E., nuclei of the columnar cells lying amongst N. 



Fig. 19. Entire ovary. X 125. 



Fig. 20. Longitudinal section of ovary in outline. X 125. 



Fig. 21. Two well-developed eggs in ovary. X325. Z'., follicle, /'.r.. Aggre- 

 gation of follicular cells. V., vitelline membrane, which is the only covering of 

 the eggs when discharged into the body cavity. 



Fig. 22. Transverse section of oviduct. X350. M.p., musculo-connective 

 tissue tunic covering the oviduct; continuous with S. of Fig. 23. E., ciliated 

 columnar cells continuous with E. of Fig. 23. 



Fig. 23. Ciliated disc (funnel) of oviduct. X 170. The Roman numerals indi- 

 cate the somites. E., ciliated cells becoming lower in ovisac (?). O., peritoneal 

 top-shaped cells covering O. in somite XIV. S., septum. L.m., longitudinal 

 muscle layer of body wall. 



Fig. 24. Spermatophore. X 70. B., flattened and expanded base for attach- 

 ment. P., pockets separated by curved partitions and all opening into chamber 

 C, which is in communication with exterior at free end of spermatophore. 



