BRANCHIURA SOWERBYI BEDDARD. 303 
Fig. 6. Section along a ventral gill, to show epithelial covering, continuation of circular muscular layer 
of body on the gill, gill cavity, and cells contained within it. x 250. 
a., branching cells within gill cavity; 6. v., blood-vessel ; cav., gill cavity ; m., muscular strands coming 
down from the transverse partition. Other references as before. 
Fig. 7. Branchiura sowerbyi ; blood-vessels to the gills; from a sketch from life, from the right side ; 
the dorsal vessel is therefore behind the intestine as seen by the observer. Of the two cutaneous branches 
shown, the one on the right is coming towards the observer and is superficial, the one on the left is on the 
deep surface. 
cut., cutaneous branch; d. g., dorsal gill; d. v., dorsal vessel; znt¢., intestine; v. g., ventral gill; v. w., 
ventral vessel, 
Fig. 8. Transverse section through gill region of Branchiura sowerbyi ; diagrammatic, constructed from 
sections to show the course of a number of vascular branches, which are not on the same level. The dorsal 
vessel d. v. gives off a dorsally directed branch d. d. to the dorsal gill, and a ventrally directed branch v. d. 
to the ventral gill. The ventral vessel v. v. gives off a branch on the right side which bifurcates into a dorsal, 
d, by. v., and a ventral division, v. br. v., going to the dorsal and ventral gills respectively. The ventral 
vessel also gives off a branch on the left side, J. br. v. 
d, g., dorsal gill; ep., surface epithelium; znt., intestine; 7. p., intestinal plexus; /. m., longitudinal 
muscular layer (the circular layer is not separately represented); v. g., ventral gill; v. m. ¢., ventral nerve 
cord. 
The section is seen from its anterior face ; right and left are therefore reversed. 
Fig. 9. Seta of Limnodrilus socialis. x 750, 
Fig. 10. Part of transverse section through the fourth segment of Limnodrilus socialis, showing the 
lateral portion of the body-wall. x 250. 
circ. m., circular muscular layer; cut., cuticle; ep., surface epithelium ; J. /., lateral line cells; long. m., 
longitudinal muscular layer; m. set., muscular bundle between setal sacs of the same side ; per'., peritoneal 
cells; s., sete. 
Fig. 11. Transverse section through sixth segment of the same. x 115. 
chl., chloragogen cells; d. v., dorsal vessel ; g/., gland-like masses of cells; @s., esophagus with ventral 
ridge projecting into lumen; s. 7. v., supra-intestinal vessel ; v. m. c., ventral nerve cord ; v. v., ventral vessel. 
Other references as above. 
Fig. 12. Portion of vascular system of the same, from the right side; from a sketch from the living. 
The anterior and posterior parts of the ventral vessel are continuous by means of a fine channel; the trans- 
verse sinus is seen in ix, and a part of the contractile loop to the genital organs. 
Fig. 13. Portion of vascular system of the same from above, showing the relations of dorsal and supra- 
intestinal vessels, the hearts, the transverse sinus and its associated plexus; from a sketch from the living. 
Fig. 14. Blood-vessels on the left side of the intestine of the same; from a sketch from the living; the 
anterior end is towards the left. The dorsal vessel is shown below the intestine. 
Fig. 15. Outline of cerebral ganglion of the same. 
Fig. 16. Longitudinal section through lower part of penis tube and sheath of the same, to show the 
shape of the lower end of the chitinous sheath and its relations. x 250, 
circ, m., circular muscular layer; ep., surface epithelium ; dong. m., longitudinal muscular layer ; per., 
peritoneal cells ; s., penis sheath ; ¢., penis tube; v. def, vas deferens ; x., shelf-like projection into lower end 
of penis sheath. 
Pt 
