MYZOSTOMIDA, a remarkable group of small parasitic worms which live on crinoid echinoderms; they were first discovered by Leuckart in 1827. Some species, such as Myzostoma cirriferum, move about on the host; others, such as M. glabrum, remain stationary with the pharynx inserted in the mouth of the crinoid. M. deformator gives rise to a gall on the arm of the host, one joint of the pinnule growing round the worm so as to enclose it in a cyst whilst M. pulvinar lives actually in the alimentary canal of a species of Antedon. A parasite is an organism that lives in or on the living tissue of a host organism at the expense of it. ... Naval Battle of Navarino by Carneray 1827 was a common year starting on Monday (see link for calendar). ...

A typical myzostomid is of a flattened rounded shape, with a thin edge drawn out into delicate radiating cirri. The skin is ciliated. The dorsal surface is smooth; ventrally there are five pairs of parapodia, armed with supporting and hooked setae, by means of which the worm adheres to its host. Beyond the parapodia are four pairs of organs, often called suckers, but probably of sensory nature, and comparable to the lateral sense organs of Capitellids (Wheeler). The mouth and cloacal aperture are generally at opposite ends of the ventral surface. The former leads to a protrusible pharynx, from which the oesophagus opens into a wide intestinal chamber with branching lateral diverticula. There appears to be no vascular system. The nervous system consists of a circumoesophageal nerve, with scarcely differ. entiated brain, joining below a large ganglionic mass no doubt representing many fused ganglia. The dorsoventral and the parapodial muscles are much developed, whilst the coelom is reduced mostly to branched spaces in which the genital product1 ripen. The esophagus, oe/œsophagus*, or gullet is the muscular tube in vertebrates through which ingested food passes from the mouth area to the stomach. ...

Full-grown myzostomids are hermaphrodite. The rnal organ consists of a branched sac opening to the exterior or each side. The paired ovaries discharge their products into a median coelemic chamber with lateral branches, often called the uterus, from which the ripe ova are discharged by a mediar dorsal pore into the terminal region of the rectum (cloaca).

This article incorporates text from the 1911 Encyclopædia Britannica, a publication in the public domain. Encyclopædia Britannica, the 11th edition The 11th edition of the Encyclopædia Britannica (1910–1911) is perhaps the most famous edition of the Encyclopædia Britannica. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ...