Dr. O'Bryen Bellingham on Irish Entozoa. 317 of Yorkshire,' vol. ii. pi. 5. fig. 5 : externally it closely resembles another species which I consider the same as Dr. Morton's fossil re-presented in Silliman's Journal, vol. xxix. pi. 26. fig. 37, and which is from the carboniferous rocks of Northumberland ; but the direction of the cartilage fulcra, as already noticed, is very different in each. I have little doubt of the fossil to which Mr. J. de C. Sowerby has applied Fleming's name Unio Urii (Brit. Animals, p. 417) being quite distinct from the shell so called, and a true Allorisma. In this case the specific name which Mr. Sowerby has given to the former may be retained, unless this fossil should hereafter be considered as a va-riety of Allorisma elongata. XXXVIII. — 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. 256.] Genus 18. Taenia. (Derived from raivia, vitta.) Gen. Char. — Body long, flat, soft, and composed of a great number of distinct articulations. Head in general larger than the neck, furnished with two pairs of oscula, suckers or discs, and often with a rostellum or prominence in front, which is surrounded or not by one or two circles of recurved hooks ; — what Rudolphi terms ' armed.' The species of this genus have been hitherto found in the bodies of vertebral animals alone, and the alimentary canal is the only part which they are found to inhabit ; they usually occur in the small intestines. They are most abundant in birds, next in mam-malia, then in fish, and lastly in reptiles. Rudolphi enumerates 146 species in his ' Synopsis/ of which 53 are doubtful. The term Taenia was employed by the ancients, but they neces-sarily confounded the genus Bothriocephalus with the Taenia. The digestive apparatus of these animals consists of two straight late-ral canals of the same diameter throughout, which commence at the oscula of the head, run backwards parallel to one another, close to the margins of the articulations, and communicate with one another by a transverse branch at the posterior edge of each articulation. The organs of reproduction are more complicated; we find male and female organs not only in every individual, but in all the larger articulations of the same individual. A small papillary projection is seen near the centre of the margin of each articu-
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