GYROCERAS. 101 



8. Gyeoceras Lbei, Whidhorne, sp. PL XII, figs. 2, 2 a. 



1889. Ctbtocebas Leei, Whidbome. Geol. Mag., dec. 8, vol. vi, p. 29. 



Description. — Shell rapidly tapering, large, much recurved. Surface covered 

 by numerous transverse rows of very foliaceous, undulating, irregular, and distant 

 lamellge, which stand out more or less perpendicularly from the shell sometimes to 

 a distance of 7 mm., and between each of which are numerous similar but much less 

 developed rows of foliaceous striae ; the whole being crossed by a few indistinct, 

 rounded, shallow, longitudinal ribs, which are narrower than their interspaces. 



8ize. — Width, 45 mm.; length, as far as seen, 93 mm. 



Locality. — Lummaton. A single specimen is in the Lee Collection in the British 

 Museum. 



BemarliS. — This fossil is distinguished from G. fimhriatum of Phillips by the 

 size and irregularity of its laminge ; and the same features separate it from 

 G. tredecimale and C. quindecimale. Mr. Foord suggests that in its ornamentation 

 it is like some American forms of the section of the family called Zltteloceras 

 by Hyatt, and we certainly find numerous Transatlantic species which approach 

 it more or less nearly in their style of marking. Its shape and curvature are very 

 difficult to make out. At first sight it appears short and slightly arched ; but 

 Mr. Crick has convinced me that it must have been a long coiled shell so imbedded 

 in the matrix that the two outlines seen in the Plate are oblique sections of the 

 same side. Thus the larger portion of the shell is lost and would originally have 

 been above the level of the Plate, and the apparent apex is only a point on the 

 lower side of the whorl. Hence it follows that in all probabihty it belongs to the 

 loosely coiled forms which are grouped under the genus Gyroceras. 



In Gyrtoceras Jason, Hall,^ the rings appear less foliaceous. 



In Gyroceras Nereus, Hall,^ these rings are more regularly and frequently 

 undulating, and present no signs of being elongated into long fimbriae ; the minor 

 ornamentation is similar, but perhaps rather coarser. 



Gyroceras Matheri, Hall,'' has the fimbriae as elongated, but much further 

 apart, and it has numerous and regular longitudinal rounded rays not seen in the 

 English shell. 



Gyrtoceras eugeninm, Hall,* appears to be a straighter shell, with stouter and 

 more distant lamellae, which are more regularly and evenly horizontal. 



1 1S79, Hall, ' Pal. N. Y.,' vol. v, pt. 2, p. 381, pi. 1, figs. 1, 2. 



2 Ibid., p. 373, pi. li, figs. 4—6. 



3 Ibid., p. 377, pi. Iv, figs. 1—6. 



* Ibid., p. 369, pi. xxxvi, fig. 5 ; pi. xlvii, figs. 5—7 ; pi. xcvi, figs. 1—11 ; aud pi. xcvii, 

 figs. 10, 11. 



