152 . A NEW rOKM OF AGELACRINITES. 



having a definite, broad, outer border; and from L. Lehouri in 

 having only 5 arms, and the arm-plates in a double row. 



The specimen figured by Bronn as L. cincinnatiensis ^ is much 

 more like our specimen. 



As it seems probable that the sixth arm of L. Lehouri is abnormal, 

 it can scarcely be taken as a specific character ; but if there were 

 only five arms the pyramid might be in the middle of the interradial 

 space, and the species would then difi'er from ours only in its larger 

 size, longer arms, and, seemingly, in a different arrangement of the 

 arm -plates. 



Until it can be shown that the differences above pointed out are 

 only such as may be due to age or individual variation, this new 

 British specimen must be held to be specifically distinct, and we 

 propose to associate our colleague Mr. Hugh Miller with the species 

 by naming it Lepidodiscus Miller i. 



EXPLANATION OF PLATE 11. 



Lepidodiscus Milleri, n. sp., from the Lower Carboniferous Limestone, near 

 Waterhead, Eiver Irthing, Cumberland. Preserved in the Museum of 

 Practical Greology. 

 Eig. 1. Test, natural size. 



Fig. 2. Test, enlarged 8^ diameters. The plates seen on each side of the arma 

 in this figure are too definitely marked off from those of the inter- 

 radial areas ; they are without doubt the upturned edges of some of 

 the interradial plates. 

 Fig. 3. Portion of an arm, enlarged, to show plates ; partly diagrammatic. 

 Fig. 4. Portion of outer band of test, to show arrangement of plates, enlarged 



28 diameters. 

 Fig. 5. Granular ornament of plates, enlarged 70 diameters. 



Discussioisr. 



Mr. Bather entreated the Authors not to revive the obsolete 

 termination ites, but, following Angelin, Loven, P. H. Carpenter, 

 Steinmann, S. A. Miller, and all recent writers on Crinoidea, 

 to write simply ' Agelacrinus ' just as they would ' CyatJiocrinus.' 

 The rarity of British Agelacrinidae, while enhancing the interest of 

 the paper, increased the difficulty of determining specific dif- 

 ferences. In the type-specimen of L. Lehouri the sixth arm was a 

 mere abnormality ; the exact position of the anus, especially in so 

 flexible a tegmen, was hardly diagnostic ; the plates bordering the 

 ambulacra in L. Milleri seemed homologous with the adambulacrals 

 of L. Lehouri. He was glad to see that the Authors made Lejpido- 

 discus a subgenus of Agelacrinus. The slight curvature of the 

 arms in L. Milleri made it approach Hemicystis; but it seemed 

 probable, from examination of Bohemian and American species, that 

 the varying curvature of the arms and the imbrication or tessel- 

 lation of the plates were not characters of more than subgeneric 

 importance. 



Mr. E. T. Newton, in reply, said that he objected to the principle 

 of altering names originally proposed, and made a point of never 

 doing so unless it was absolutely necessary. 



^ ' Lethsea Geognostica,' tab. iv^. fig. 6. 



