Monobotryllus violaceous   Oka  (Sea Squirt)
Organism information awaits expert curation
Class: Ascidiacea


Solitary ascidian. Ovoid, much depressed, attached by whole of the undersurface. The test is thin but tough and leathery. In the marginal region blood vessels with terminal knobs are found as in Botryllus. Mantle is very thin and transparent with no specially developed musculature. Tentacles are simple, filiform with pointed tips, 20 in number in two sizes alternating. Branchial sac occupies a large part of the internal cavity. Stigmata broad and short, sometimes oval, arranged more or less regularly on both the sides of the endostyle. Endostyle is long and narrow. Dorsal tubercle is longitudinally elongated, with a short simple slit-like opening. The nerve ganglion lies immediately behind the dorsal tubercle. Dorsal lamina is a long, narrow, plain membrane. Alimentary canal is a simple loop of the oesophagus, stomach and intestine, placed under the posterior position of the branchial sac. A number of small polycarps project from the walls of the peribranchial cavity, arranged in two rows, one on each side of the endostyle.

Synonym (s)

Common Name (s)
Economic Importance and Threats



• Orissa, Puri INDIA

Literature Source(s)
  • Sebastian, VO and Kurian, CV (1981) Indian Ascidians Mohan Primlani, Oxford & IBH Publishing Co., New Delhi 153 pp Available at - NIO, Goa
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -

Page last updated on:13-04-09

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