In the curious hydroid Monobrachium a single tentacle is present, and the same is the case in Clathrozoon; in Amphibrachium and in Lar (fig.
Protohydra occurs in oysterbanks and Monobrachium also grows on the shells of bivalves, and both these hydroids probably fish in the currents produced by the lamellibranchs.
11), Monobrachium, &c.
- The genus Monobrachium is a colonyforming hydroid which grows upon the shells of bivalve molluscs, each polyp having but a single tentacle.
C. Mereschkowsky, " On a new Genus of Hydroids (Monobrachium) from the White Sea, with a short description of other new Hydroids," Ann.
Wagner, " Recherches sur l'organisation de Monobrachium parasiticum Merejk," Arch.