E M N E N 331 19 ._ pmdiv , c ma or flageiium; a, oesophagus ;
- - stomach; cs, cesophageal out-
gvowth for i atera i organ; am, amnion; pr.d., prostomial disk; po.d.. metastomial disk.
being characterized by peculiar larval forms, the second developing without metamorphosis. The larva of Cerebratulus is called the pilidium. In exterior shape it resembles a helmet with spike and ear- lobes, the spike being a stro&g and long flagellum or a tuft of long cilia, the ear-lobes lateral ciliated appendages (fig. 19). It encloses the pri mitive alimentary tract. Two pairs of invaginations of the skin, which originally are called the prostomial and meta- 0.771 stomial disks, grow round the intestine, finally fuse together, and form the skin and muscu- lar body-wall of the future Nemertme, which afterwards V>ppnmp piliatpr) frpps itsplf liaiea, ] .IbLU from the pilidium investment, j j i . ,1 j i. and develops into the adult worm without further metamorphosis (2, 13). The eggs of these species are not enveloped by such massive gelatinous strings as are those of the genus Linens. In the latter we find the young Nemertines crawling about after a period of from six to eight weeks, and probably feeding upon a portion of this gelatinous substance, which is found to diminish in bulk. In accordance with these more sedentary habits during the first phases of life, the characteristic pilidium larva, which is so eminently adapted for a pelagic existence, appears to have been reduced to a close-fitting exterior layer of cells, which is stripped off after the definite body-wall of the Nemertine has similarly originated out of four ingrowths from the primary epiblast. To this reduced and sedentary pilidium the name of " larva of Desor " has been given (1). In the Hoplonemertea, as far as they have been investi gated, a direct development without metamorphosis has been observed. It appears probable that this is only a further simplification of the more complicated metamor phosis described above. As to the development of the different organs, there is still much that remains doubtful. The hypoblast in some forms originates by invagiuation, in others by delamina- tion. The proboscis is an invagination from the epiblast ; the proboscidian sheath appears in the mesoblast, but is perhaps originally derived from the hypoblast. The origin of the lateral organs has already been noticed ; that of the nerve system is essentially epiblastic. Literature. (1) J. Barrens, " Recherches sur 1 embryologie des Nemertes," Annales des Sc. Naturellcs, vi., 1877 ; (2) 0. Biitsclili, "Einige Bemerkungen zur Metamorphose des Pilidium," Archiv fur Naturgcschichte, 1873 ; (3) L. von Graff, Monographic dcr Tur- bellaricn, 1882; (4) A. A. W. Hubrecht, " TJntersuchungen iiber Nemertinen a. d. Golf voa Neapel," Nicderl. Archiv filr Zoologic, ii. ; (5) Id., "TheGeneraof EuropeauNemerteanscriticallyrevised," Notes from the Lcydcn Museum, 1879; (6) Id., "Zur Anatomic u. Physiologie d. Nervensystems d. Nemertinen," VcrJi. Kon. Akad. v. Wctcnsch., Amsterdam, 1880, vol. xx. ; (7) Id. ," The Peripheral Nervous System of the Palceo- and Schizonemertini, one of the layers of the body-wall," Quart. Journal of Micr. Science, vol. xx. ; (8) Id., " On the Ancestral Forms of the Chordata," lb., July 1883 ; (9) W. Keferstein, " Untersuchungen iiber niedere Seethiere," Zcitschr. f. wissensch. Zool., vol. xii., 1863 ; (10) J. von Kennel, "Beitrage zur Kenntniss der Nemertinen," Arbeiten a. d. sool.-zoot. Instil., ii., Wiirzbtirg, 1878; (11) W. C. Macintosh, A Monograph of British Annelida: I. Nemcrteans, Ray Society, 1873-74 ; (12) A. F. Marion, " Recherches sur les animaux iiiferieurs du Golfe de Marseille," Ann. des Sc. Nat., 1873 ; (13) E. Metschnikoff, "Studien iiber die Entwickelung der Echinodermen und Nemertinen," M6m. de r Acad. Imp. de St. Petcrsb., xiv., 1869; (14) Max Schultze, Beitrage zur Naturgcschichte der Turbcllarien, Greifswald, 1851, and Zci Isckr. fur wissensch. Zool., iv., 1852. (A. A. W. H.) NEMESIANUS, a Roman poet who flourished about 283 B.C. His full name was Marcus Aurelius Nemesianus Olympius, and he is called a Carthaginian. He was an admired and popular poet at the court of the Roman emperor Cams. He wrote poems on the arts of fishing and hunting, but only a fragment of the latter, 325 hexameter lines, has been preserved. It is neatly ex pressed in good Latin. Some other extant fragments are ascribed without good authority to this poet. Editio princcps, Venice, 1534. The Cynegetica of Gratius Faliscus and Nemesianus are united in the edition of R. Stern (Halle, 1832), and are added to M. Haupt s edition of Ovid s Halicutica (Leipsic, 1838). NEMESIS occasionally appears as a Greek goddess. At Rhamnus in Attica she had a famous temple, and there was an Attic legend that Helen was the daughter of Nemesis. The Attic goddess was perhaps a form of Aphrodite, who sometimes bears the epithet Nemesis. In Smyrna and the neighbouring Temnos we find a pair of goddesses of the name. They are represented on coins of these cities, and it is said that they appeared in a dream to Alexander the Great, bidding him rebuild Smyrna. They are certainly connected with the cultus of Meter Sipylene or Cybele, the tutelary goddess of Smyrna and all the country round Mount Sipylus. In general Nemesis appears as a personification of that righteous indignation which punishes the arrogant and tyrannical abuse of pro sperity. Often the idea is carried much further than this; in Herodotus especially the divine Nemesis is offended by all great prosperity among men, quite irrespective of the moral guilt of the persons concerned. NEMESIUS, a Christian philosopher, author of a treatise On Human Nature, was, according to the title of his book, bishop of Emesa (in Syria) ; of his life nothing further is known, and even his date is uncertain, but most probably he flourished towards the close of the 4th century. Theologically, and especially as regards his christology, he is usually claimed by the orthodox ; but his views as to the pre-existence of the soul and a modified metempsy chosis are more Platonic than catholic, and his leaning towards the doctrine of the world s eternity is difficult to reconcile with what, afterwards at least, came to be the teaching of the church. One or two of his physiological expositions have occasionally been quoted, very irrelevantly, to show that Harvey s discovery of the circulation of the blood had been anticipated at that early age. Nemesius is frequently quoted by later writers of the Eastern Church, such as Joh. Damascenus. His writings have sometimes been attributed to Gregory of Nyssa. The editio princeps of the ircpl <vo-eo>s avOpwTTov appeared at Antwerp in 1565; the work has more than once been re-edited and translated. NENAGH, a market and assize town of county Tipperary, province of Munster, Ireland, is finely situated in a rich though hilly country near the river Nenagh, 29 miles north of Tipperary and 95 south-west of Dublin. The principal buildings are the court-house, the barracks, and the market-house. Of the old castle, "Nenagh Round," dating from the time of King John, there still exists the circular donjon or keep. There are no remains of the hospital founded in 1200 for Austin canons, nor of the Franciscan friary, founded in the reign of Henry III. and one of the richest religious houses in Ireland. The town depends chiefly on agriculture, and there is an important butter and corn market. The population in 1871 was 5696, and in 1881 it was 5422. Nenagh was one of the ancient manors of the Butlers, who received for it the grant of a fair from Henry VIII. In 1550 th* town and friary were burned by O Carroll. In 1641 the town was taken by Owen Roe O Nial, but shortly afterwards it was recaptured by Lord Incliiquin. It surrendered to Iretou in 1651^ and was burned by Sarsfield in 16S8.
