TRIGONOCERAS PARADOXICUM. 51 



Only one specimen has been, up to the present time, found in Ireland, viz. 

 M'Coy's type, figured in the "Synopsis" {loc. clt.). This was formerly in the 

 collection of the late Dr. Haines of Cork. M'Coy's figure of it is " restored," 

 unless it has sufi'ered damage since it was introduced into his work. 



Locality. — Little Island, near Cork. 



Familij Trigonoceeatid;e:. 



Genus Teigonoceijas, M^Coij, 1844. 



Tbigonoceras pauadoxicum, J. de C. Soiverhy, sp. Plate XVIII, figs. 'Sa,h,c, 



4 a, h, 5. 



1825. Obthoceka pakadoxica, J. de C. Sowerby. Min. Couch., vol. v, p. 81, 



pi. cccclvii. 

 183G. Oethockbas pauadoxicum, J. Fhillips. Geology of Yorkshire, pt. 2, 



p. 239. 

 1844. — (Tkigonoceeas) paradoxicum, F. M'Coy. Syuop. Carb. 



Foss. Ireland, p. 9. 

 1855. — — — F. M'Coy. British Palaeo- 



zoic Fossils, fasc. 3, 

 p. 573. 

 1880. GxEOCEBAS PABADOXicuM, L. G. de Koninck. Faune Calc Carb. Belgique 



(Ann. Mus. Eoy. d'Hist. Nat. Belgique, 

 torn, v), pt. 2, p. 7, pi. .\xxii, figs. 3, 3a,Sh. 

 1883. Trigonocebas paradoxic um, A. Hyatt. Proceed. Boston Soc. Nat. Hist., 



vol. xxii, 1882—3 (1884), p. 291. 

 1891. Gteocebas (Tbiuonocebas) pabadoxicum, A. H. Foord. Cat. Foss. 



Ceph. Brit. Mus., pt. 2, p. 70, fig. 7. 

 1893. Trigo^'OCEBas pauadoxicum, A. Hyatt. Carboniferous Cephalopods. 



Second paper. Geological Survey of 

 Texas, Fourth Annual Eeport, 1892, 

 p. 404. 



Description. — Shell rapidly tapering, " abruptly incurved towards the smaller 

 t'lid, forming half a volution " (M'Coy), the rest of the shell gently curved. In a 

 givea specimen it was found that upon a cord of 130 mm., subtending the con- 

 cave side of the shell, the greatest curvature was 20 mm. The section is 

 distinctly shield-shaped, the ventral area slightly concave, the sides, at first 

 nearly straight, are curved below, converging towards the median line, where there 

 is a ridge or keel which is not very prominent. Two strong keels on each side 

 of the peripheral area run parallel to the marginal one (PI. XVIII, fig. 4 h). The 



