HAPLOCRINUS. 205 



1. Haplocrinus decipiens, Whidborne. Plate XXIII, figs. 9, 9 a. 



1889. Haploceintjs decipiens, Whidborne. Geol. Mag., dec. 3, vol. vi, p. 79. 



Description. — Calyx minute, subglobose, rather low, pentagonal in transverse 

 section at the springing of the arms. (Basal plates unseen.) Radials horizontally 

 straight above, produced in the centre to form on the upper margin a squarish 

 greatly-protruding arm-facet, which is deeply excavated upon its upper surface ; 

 while the sides of adjoining radials form a nearly flat surface. Oral plates five, lai'ge, 

 elevated, triangular, with flat lower margins and concave lateral margins, forming 

 together a low pentagonal pyramid with wide oval grooves at the angles, and 

 with each side resting on two of the radials. Posterior oral wider than the rest, 

 and apparently produced over the apex in a central tongue. Postero-lateral orals 

 narrow. 



Size of calyx. — Height about 5 mm., width 5 mm. 



Locality. — A single specimen is in my Collection from Lummaton. 



Remarks. — When first discovered only the upper part of this little fossil was 

 visible, and it was then supposed by my friend Mr. J. E. Lee and myself to be a 

 Pentremite ; 1 on submitting it, however, to Mr. P. H. Carpenter, he succeeded in 

 clearing away the matrix and proving it to belong to the genus Haplocrinus. The 

 specimen, however, still remains too much confused with the matrix to allow its 

 details to be accurately described, the basals and lower radials being hidden, and 

 lower parts of the upper radials being obscured, though their lateral sutures 

 are seen. The upper part of the specimen is more distinct. The facets 

 for the arms are greatly developed, forming definite squarish prolongations 

 from the centres of the radials ; the articular faces of the radials are separated 

 from the oral plates by a deep impressed line ; the oral plates are laterally 

 concave, and so bevelled that their external summits end at some distance below 

 the apex. Here again the fossil becomes indistinct, so that it can only be said 

 that the posterior plate appears (had it been perfect) to have surpassed the others. 



Affinities. — This fossil is so much like E. stellar is, F. Romer, 2 that it may be a 

 question whether it is specifically distinct. Judging, however, from Romer's 

 figure, the German species has a shallower and more expanding calyx, its radials 

 are much less erect, its tegmen is considerably higher than the dorsal cup, and 

 the grooves between the oral plates are narrower. It therefore seems that the 

 English fossil is most probably distinct. 



1 1881, Whidborne, ' Geol. Mag.,' dec. 2, vol. viii, p. 288. 



2 1844, F. Eomer, ' Rhein. Uebergangsgeb.,' p. 63, pi. iii, figs. 5 a — d. 



