Teleost

Another curious Teleost is the Sea Horse.

Source: tatoeba (10652489)

1969, W. S. Hoar, D. J. Randall (editors), Fish Physiology, Volume 2: The Endocrine System, page 156, There are no direct studies of the effects of arginine vasotocin or 4 Ser, 8 Ile oxytocin in the holostean bony fish. It can only be suggested that the histological evidence suggests a possible role in the control of the adenohypophysis and that systemic effects might well parallel those found in the closely related teleosts.

Source: wiktionary

After antigenic stimulation, increased amounts of lymphoid tissue does appear, in the spleen of teleosts. The lymphoid tissue of teleost spleen consists of lymphoid cells, mainly small, medium, and large lymphocytes arranged in a supporting reticular cell meshwork.

Source: wiktionary

Nevertheless, an element of real danger adds a piscine frisson to most encounters with this mysterious teleost.

Source: wiktionary