Sentence Examples with the word ventral fin

In the genus Branchiostoma the metapleural folds terminate symmetrically shortly behind the atriopore, but in Heteropleuron the right metapleur passes uninterruptedly into the median crest of the ventral fin (fig.

The ventral fin is also elongated, and all the fins are destitute of spines.

The keel of the ventral fin is continued past the anus into the expanded caudal fin, and so it happens that the anal opening is displaced from the middle line to the left side of the fin.