Dr. O^Bryen Bellingham on Irish Entozoa. 167 XXII. — Catalogue of Irish Entozoa, with observations. By O^Bryen Bellingham, M.D., Fellow of and Professor of Botany to the Royal College of Surgeons in Ireland, Member of the Royal Zoological, Geological and Natural History So-cieties of Dublin, &c. [Continued from p. 105.] Order 1. NEMATOIDEA. Genus 8. Ascaris. (Derived from aaKapi^w, salio.) Body cylindrical and elastic, attenuated more or less at the extre-mities. Mouth terminal, provided with three tubercles, one of which is superior, two inferior. Anus a transverse cleft close to the posterior extremity. Male organ a double spiculum without any sheath. Female organ opening externally about the junction of the anterior with the middle third of the body. The name Ascaris was given to this genus by Linnseus on ac-count of the liveliness of the motions of some of the species, and it has been adopted by all zoologists since. The species are very numerous, 140 being enumerated by Rudolphi in his ' Synopsis.' They occur in mammalia, birds, reptiles and fish ; their most common habitat is the alimentary canal. Rudolphi has made three divisions of the genus. The first contains the species which are equally attenuated at each extremity. The second, those in which the anterior extremity has a greater diameter than the posterior. The third, those in which the posterior extremity has a greater diameter than the anterior. Each of these divisions Rudolphi has again subdivided accord-ing as the head is provided with lateral membranes (what he calls winged), or as this part is naked or destitute of these ap-pendages. Corpore utrinque cequaliter attenuate ; capite nudo, 1. Ascaris lumbricoides*. Small intestines of man (Homo). * The Ascaris lumhricoides (or common round worm of the human intestines) has been known longer than any other species of Ento-zoon ; it is included in Pennant's and Turton's list of the British species ; it is not peculiar however to the human subject, for it oc-curs also in the intestines of the ass, wild-boar, pig and ox : the spe-cies found in the horse, although for a long time confounded with it, and resembling it in some points, is now known to be distinct. The Ascaris lumhricoides inhabits the small intestines of the human i«ubject ; the female is much larger than the male, and is much nwre
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