202 MR. R. H. BURNE ON ELASTIC [ Mar. 2, 
Herrings and also in the Sturgeons, and it is_ particularly 
interesting to note that in both these groups of Fishes the aorta 
has a similar character, being a wide capacious vessel enclosed 
Text-fig. 20. 
A transverse section through the vertebral column and aorta of a Shad, 
in the region of the trunk. 
A. Aorta. D.L. Dorsal elastic ligament. H.A. Hemal arch. M.* Suspensory 
membrane of the ventral ligament. N.SP. Neural spines. V.B. Body of 
vertebra. V.L. Ventral ligament. 
within a more or less complete skeletogenous and unyielding 
sheath. This is particularly so in the Sturgeon, where the vessel 
