Quarterly journal of microscopical science . l region, and if the same distance between themis retained over the length of the genital region there oughlto be some 120 pairs of gonads and gonopores. The outer and inner lobes of the . are separated bya lateral septum which extends from the region f til. linethe gonopores to the dorsal genital groove, and il 588 ALEXANDER MEEK displayed in all the sections figured. This is the dispositionof the septum in the branchial region, but with the disappear-ance of the gills the septum is extended medially to be attachedto the upper part of the po
Quarterly journal of microscopical science . l region, and if the same distance between themis retained over the length of the genital region there oughlto be some 120 pairs of gonads and gonopores. The outer and inner lobes of the . are separated bya lateral septum which extends from the region f til. linethe gonopores to the dorsal genital groove, and il 588 ALEXANDER MEEK displayed in all the sections figured. This is the dispositionof the septum in the branchial region, but with the disappear-ance of the gills the septum is extended medially to be attachedto the upper part of the post-branchial alimentary is obvious, therefore, that in the branchial region of thebody the septum forms a cavity for the inner branch ofthe gonad, and that this cavity excludes this branch of thegonad from the space between the dorsal wall of the bodyand the branchial region of the alimentary canal ; or, toput it another way, from the space between the dorsal Text-figs. 12 and 13. dorsal vessel gill pore gen groove Qonopore. margingen wirf?? sperms 12 S3 Fig. 12.—A more detailed view of a section of the margin of thegenital wing through the gonopore. Fig. 13.—Section through a gill-pore of the right side to show dis-position, the gill skeleton in section with synaptieula. and theinsertion of the lateral septum to the genital groove. genital groove and the dorsal mesentery. The gill-poresare, therefore, not merely medial to the gonopores, they aremedial to the gonad. The outer lobe could certainly pene-trate this region but it does not do so. It is only behind thebranchial region that the displacement of the septum to thewall of the gut permits of the inner branch of the gonadinvading this region of the body cavity. This is a feature ofimportance, for it is the disposition of the septum and thegonad in the genus Glossobalanus, and it has been discussedby Spengel in the monograph and in his paper on Glosso- GLOSSOBALANUS MABGINATUS 589 balanus elongatus (1904). The s
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