532 Dr. H. Woodward — On the Genus Cyclus. 



nodules of tlie Coal-measures, Coseley, Staffordshire, that the form 

 which I had described in 1868 as Cyclus Banhini, from Carluke, 

 and which differed in so very remarkable a manner from all the 

 other carapaces referred to that genus from the Carboniferous Lime- 

 stone, was really the underside of a Cyclus from which the shield 

 or carapace had been removed. Unfortunately at that time I had not 

 seen Mr. B. N. Peach's paper, nor was I aware that he had written 

 upon the genus, until my paper on Cyclus Scotti, in 1893, was in 

 print, when I added a note apologising for having overlooked it.^ 



To Mr. Peach, therefore, belongs the merit of having been the first 

 to explain (in 1883) the true nature of the peculiar structure observed 

 in C. Banhini. But the interpretation put upon the genus by Mr. 

 Peach remains to be considered. And here let me express my 

 thanks to Sir A. Geikie, the Director-General, for granting me 

 permission to study the original specimens of Cyclus, described by 

 Mr. Peach, which Mr. J. G. Goodchild, in charge of the Survey 

 Collection in Edinburgh, has most kindly forwarded to me. 



An examination of these specimens at once reveals the extreme 

 difficulties which Mr. Peach encountered in endeavouring to de- 

 cipher these very obscure little organisms, most of which have had 

 the details of their structure almost entirely obliterated by deposits 

 of globular or orbicular calcite.^ 



I was fortunate also in obtaining twenty specimens of Cyclus 

 testudo from Eskdale, early in the present year, from Mr. T. Stock ; 

 and, although most of these were similarly obscured by calcite- 

 deposits, I have obtained some good results, which I will presently 

 refer to. 



The best preserved specimens which Mr. Peach had the good 

 fortune to secure, not only show traces of an upper dorsal shield, 

 but also evidence of the ventral surface with its sterna and radiating 

 apodemata, as figured by me, in 1868, in C. BanTiini from Carluke, 

 and also in our present Plate XV. Fig. 8. Thus the enigmatical 

 Cyclus Banhini — as Peach points out, and as the specimens here 

 figured conclusively prove — is in reality the sternal surface of a 

 Cyclus, the dorsal shield of which may, or may not, be known. 



So far, we are in general agreement ; but when Mr. Peach proceeds 

 to suggest that I have mistaken the anterior for the posterior end 

 of these carapaces, I am at once at issue with him, and can only 

 conclude that the " globular calcite " has obstructed his clearer 

 vision. Nor is it necessary to institute any very lengthy comparisons 

 with other forms in order to ascertain, as in the famous Skye-terrier 

 controversy, " which is his head and which is his tail." We are, 

 fortunately, not dependent upon the Langholm specimens alone for 

 settling this fundamental point, for in the numerous and beautifully 

 preserved examples from Mr, Henry Johnson's collection we have 

 evidence enough to establish our position beyond a doubt. 



1 See Geol. Mag. 1893, Dec. III. Vol. X. footnote, p. 29. 



" See note, p. 482, on globular calcite, on a new species of Euryptenis from 

 Eskdale, by H. Woodward, Geol. Mag. 1887, Dec. III. Vol. IV. pp. 481-484, 

 PI. XIII. 



