﻿0GYG1A. 



125 



Genus — Ogygia, Brongniart, 1822. 



Flat or very slightly convex, with wide semicircular head, large many-ribbed tail, and 

 slightly pointed body-segments. The glabella well marked, wider in front, and with four 

 lateral furrows. The eyes large, lunate, depressed, and smooth. Facial suture generally 

 marginal in front. The hypostome continuous, the labrum pointed. 



The thorax has a narrow very distinct axis, and the pleurae are pointed, strongly 

 grooved, and have a very obscure and remote fulcrum, so that the animal could only 

 bend, not roll up completely (and it is probable that some of the species never did so). 

 The tail has many segments : these are very distinct, and generally strongly duplicate. 



Range. — Lower Silurian only. North and central Europe : not yet known in America 

 (or the southern hemisphere ?). The species are rather numerous, and often attain a great 

 size, but not so large as that of Asaphus. 



Ogygia Bucnii, Brongn. PI. XIV, figs. 1—7 ; PI. XV, figs. 1—6. 



Br. Llhwyd, in the Philosoph. Trans., vol. xx, 279, tab. addit., fig. 15, 1698. 

 Buglossa curia strigosa, ib., Iclinograph. Brit. Epist. 1, t. xxii, fig. 2, 1G90. 



Trilobite from Llanelly, Parkinson, Org. Rem., vol. iii, t. xvii, fig. 13, 1811. 

 Asaphus de Buchii, Brongniart. Crust. Foss. t. ii, fig. 2, 1822. 

 Trilob. de Buchii, Schlotheim. Nachtr. ii, 34 (excl. the locality " Norway"), 1823. 

 Asaphus Buchii, Balman. Paleadse., 68, 1826. 



— — J.B. C. Sowerby. Loudon's Mag. Nat. Hist., vol. ii, fig. 27, 1S29. 



— — Buckland. Bridgwater Treatise, t. xlvi, fig. 7, 1836. 



— — Murchison. Sil. Syst., t. xxv, fig. 2, 1837. 



- — Quenstedt. Wiegm. Archiv, vol. iii, 1, 346, 1837. 



— — Emmerich. Dissert. 28, 1839. 



— — Milne-Edwards. Crust. 3, 309, 1840. 



i — — Burmeister. Org. Trilob., t. i, fig. 2, 1843, Ray edition, p. £9, 



(facial suture wrongly figured), 1846. 



— — Corda. Bb'hm. Tril., t. iv, fig. 39 (bad), 1847. 



— — Barrande, Sil. Syst. de Boheme, pi. ii A, f. 25, 26, 1852. 

 Ogygia Buchii, Salter. Decade II, Geol. Survey, pi. vi, 1849. 



Junior. PI. XIV, figs. 5, 6. 



Tiunucleus? asaphoides, Murchison. Sil. Syst., t. xxiii, fig. 6, 1837. 



— — Milne-Edwards. Crust, v, iii, 333, 1840. 



0. ovalis 5 — 1-uncialis, capite semicircular}, glabella angustd utrinque quinquesulcatd, 

 oculis ad medium capitis ; spinis posiicis brevibus ; labro obtuse acuminato ; thoracis axe 

 bis pleura angustiore, — caudce longo abruplo ; sulcis lateralibus 1 2 — 14 perduplicatis, prope 

 marginem angulathn deflexis. 



