298 WILLIAM BLAXLAND BENHAM. 
Fic. 8.—Problematic organ attached to the posterior face of the anterior 
septum (s.) of somite x11, labelled (y) m Fig. 4. (x 10.) 
Fic. 9.—A spermatheca, seen as a transparent body when mounted in 
glycerine. spa. The spermatozoa within it. sptho. The fixed end of the 
organ, leading to the exterior. w. sp. The muscular wall, lined within by 
columnar epithelium. 
Fie. 10.—A spermatozoon. 
Fic. 11.—A portion of a section through a seminal reservoir, showing the 
thick trabecule (¢. ct.), which divides the cavity (cav.) up into small chambers. 
b. v. Blood-vessels traversing the trabecule. spe. The developing spermatozoa. 
Fie. 12.—A transverse section through the testicular prolongation of the 
seminal reservoir, showing the enclosed testis (¢.) attached along its outer 
wall. sem. res. A portion of the adjoining seminal reservoir. 
Fic. 13.—A more enlarged and detailed drawing of the same. (The 
lithographer should have made this relatively larger than Fig.12.) dv. Blood- 
vessel from the wall of the sac passing into the substance of the testis. 
cav. cavity of the sac. ¢.¢. Connective tissue of the wall of the sac. 
spm. Sperm-mother-cells. 
Fic. 14.—A portion of the septum (s.) between somites x1I and XIII, to- 
gether with the ovary, on its posterior face, and the problematic organ (#, in 
Fig. 4) on its anterior face. Hach lobule of the ovary (ov. /.) is made up of 
celomic epithelial cells (c. ep.), which are not shown, and ova (ov.). The edge 
of the funnel-shaped organ (Fig. 7) is fringed with ciliated processes (ap), of 
which a few are here shown. 
Fig. 15.—The heart-shaped swelling of the dorsal trunk in somite v111, 
seen from the dorsal surface. g. An apparent groove, which is really only 
due to the close approximation of the two parts of the double dorsal trunk. 
8. 8. The septa. 
Fic. 16.—The heart-shaped organ after removal of its dorsal walls, to show 
its double character and thickened walls. The two halves have been stretched 
apart slightly, in order to show that the groove is really a division. com’. A 
portion ofa lateral heart, leaving the dorsal vessel just behind a valve (va. ¢.), 
in each side. Similar valves (va. c.) are shown in the anterior part of the 
dorsal vessel. S. Septum. 
Fie. 17.—A portion of the dorsal trunk (D.) laid open, to show the valves 
within. d. spt. A vessel from the septum (m) entering the dorsal trunk 
anteriorly to the small valve (va.). The vessel to the intestine (d. in?.) leaves 
the trunk just behind the valve (va. 7.). 
Fic. 18.—A portion of a “lateral heart.” m. A band of circular muscles 
causing the ampullate appearance. gr. The narrow proximal portion where it 
is joimed to the dorsal trunk. 
Fie. 19.—A diagrammatic section through the body, to show the arrange- 
ment of the vascular trunks anteriorly to somite x1. The arrows indicate the 
