Morphogenesis of the digestive tract in the fetuses of the southern minke whale, Balaenoptera acutorostrata

Abstract

Gross and histological observations on the digestive tract in 15 fetuses of the southern minke whale (Balaenoptera acutorostrata) with C.R.L. from 37.2 to 1,940mm revealed that the fetal stomach formation in this species resembled that of the ruminant, i.e., the compartment 1 arose from the stomach bud, but not from the esophagus to form the forestomach. The differentiated gastric glands, the parietal cells, were detected in fetuses with more than 213.0mm C.R.L. The circular folds resembling intestinal haustra like circular folds without tenia were detected on the cecum in fetuses with more than 650mm C.R.L. and less than 1,070mm C.R.L. The similar structure was seen in large intestine in fetuses with more than 650mm C.R.L.