http://c8.alamy.com/comp/MA7C58/the-elasmobranch-fishes-fig-197-diagram-of-relations-of-postcardinal-to-lateral-abdominal-system-squalus-suctclii-brv-brachial-vein-hsc-brachioscapular-cov-coracoid-vein-dc-duct-of-cuvier-lav-lateral-abdominal-vein-lcv-lateral-cutaneous-vein-pcs-postcardinal-sinus-sclv-subclavian-vein-sscv-subscapular-vein-after-entering-the-subscapular-may-pass-dorsally-into-the-postcardinal-sinus-or-ventrally-into-the-lateral-abdominal-vein-in-other-words-if-the-sub-scapular-vein-of-squalus-sucklii-had-no-connection-with-the-postcardinal-sinus-squalus-woul-MA7C58.jpg