68 W. BALDWIN SPENCER. 



Fig. 38.— Side view of a hook with its basal joint. The numbers indicate 

 the different parts to which muscles are attached, and the letter /indicates 

 the point on either side which acts as a fulcrum. 



Tig. 39.— Diagrammatic representation of a side view of the outer hook of 

 the left side, together with its muscular apparatus. The different muscles are 

 lettered, and they are described under these letters in the text. The numbers 

 correspond to those in Fig. 38. The drawing represents the results of exami- 

 nation of dissections, and of continuous series of sections. 



PLATE VII. 



List of References. 



Ace. F. Acessory gland of female. C. S. 0. Central cavity of ovary. 

 C. S. E. Epithelium of cirrus-sac. Co. Od^ Swollen portion of united ovi- 

 ducts. Co. Od.y Thick-walled muscular portion of united oviducts. Cu. 

 External cuticle. Cu. C. S. Cuticle lining cirrus- sac. Ctt. Vg. Cuticle lining 

 vagina. E. Subcuticular epithelium. E^. Epithelium around opening of 

 hook-gland on papilla. Ej. D. E. Epithelium lining ejaculatory organ of male. 

 Gl. Vg. Gland-cells in wall of vagina. L. S. 0. Lateral pouch of ovary. 

 M. C. S. Muscle in wall of cirrus-sac. M. Ej. D. Muscle in wall of ejacu- 

 latory organ. M^. Muscle band from upper wall of united portion of oviducts 

 to upper wall of uterus. Mes. Mesentery supporting ovary. M.P. Mem- 

 brana propria. Od. oviduct. 0. Ek. Gl. Opening of hook-gland on papilla. 

 0. V. S. Opening of vesicula seminalis into vas deferens. S. Shell around 

 ovum. S.O. Sense-organ. Sp. Spermatheca. Sp.D. Ductof spermatheca. 

 Sy. Masses of protoplasm containing nuclei in dorsal wall of ovarian tube. 

 U. Uterus. V. D. Vas deferens. V. S. -Vesicula seminalis. Vg. Terminal 

 vagina. Vg. E. Epithelium of vagina, x. Thick cuticular layer in wall of 

 vagina. 



EiG. 40. — Diagrammatic representation of a much enlarged side view of a 

 portion of the reproductive organs of a mature female. The whole of the 

 spermatheca of one side and the upper half of that of the other is cut away. 

 The two oviducts are seen to unite to form a common portion, which is joined 

 ventrally by the uterus, and laterally by the spermathecal ducts. A special 

 muscle baud passes over from the common portion of the oviduct to the upper 

 wall of the uterus. A portion of the muscle band is cut away to show the 

 accessory gland. 



Fig. 41. — Diagrammatic representation of a horizontal longitudinal section 



through the portion of the female reproductive organs represented in Fig. 40. 



Fig. 42. — Longitudinal section through the junction of the portion of the 



vagina which serves as a uterus and the terminal vagina to show the sudden 



thickening which takes place to form the walls of tiic latter. Zeiss, A, oc. 2. 



Fig. 43. — Transverse section across the ovary of a mature female. The 



