O IR I Gr 1 1ST A. Ij AETICLBS. 



♦ 



I. BUNAIA WOODWAXDI, A New MEROSTOME FROM THE SlLURIAN 



Waterlimes of New York. 



By John M. Clarke, LL.D., For. Corr. Geol. Soc. Lond., Director of the 

 New York State Museum, Albany, N.Y., U.S.A. 



(PLATE XIV.) 



Prefatory remark by author. — Dr. Henry Woodward has asked me to 

 prepare for the Geological Magazine a brief sketch of this new fossil. It 

 seems to me most appropriate that the Magazine, the sturdy child of this 

 eminent and venerable palaeontologist, and the expositor of so many of his own 

 observations on Palaeozoic Crustacea, should carry the first printed account of 

 this discovery, which I have taken pleasure in dedicating to Dr. Woodward, 

 my colleague and friend of many years. 



! MHE hydraulic limestone series 'which cap the Silurian rocks of 

 _L the New York sections, and are commonly embraced under the 

 name " Salina Group", are probably the richest known depository 

 of remains of the Merostome Crustacea. During the past fifteen 

 years we have been engaged upon the study of this fauna, and the 

 results at which we arrived in our memoir on the Eurypterida of 

 New York ' could not have been safely attained without the previous 

 labours of Dr. Woodward and the late Professor Rupert Jones, of 

 Huxley, and Hugh Miller for the British species; of Eriedrich 

 Schmidt, Nieszkowski, and Holm for the species of the Baltic basin. 



We now recognize in the Salina basin of New York over sixty 

 species of the Eurypterida (Eurypterus, Pterygotus, Dolichopterus, 

 Stylonurus, etc.), and to this large number are to be added two 

 species of the rare genus Pseudoniscus, which had heretofore been 

 found only in the Baltic beds. In the North European development 

 of this shallow-water coastal bay fauna there are three genera of 

 Merostomes which the New York deposits have never revealed ; 

 ITemiaspis and JVeolimulus, from the Scottish Silurian, and Bunodes 

 from the Island of Oesel. What we are now designating by the 

 name Bunaia may be regarded as an alternative expression of 

 Bunodes, which according to the descriptions by Eichwald, Schmidt, 

 Nieszkowski, and more recently by Patten {The Vertebrates and their 

 Kin) is a creature 2-3 inches long, with short semicircular head, 

 a broad mesosoma of six segments, followed by three narrow 

 segments of the post-abdomen and a long single telson-spine. The 

 head is marked by five curved radial furrows diverging on each side 

 from the central subtriangular glabellar elevation ; and these 

 divide the surface into corresponding radial ridges. Dr. Patten has 

 called attention to the retention of this primitive structure in the 

 Limulus embryo, a fact which certainly seems to bespeak the direct 

 descent of the latter from this ancient primitive merostome. 



The New York fossil is like Bunodes in these cephalic structures. 

 Though of very much smaller size, the carapace shows on the upper 

 surface the same arrangement of parts, and on the underside this 



1 Clarke & Ruedemann, Mem. 14, pts. 1, 2, N.Y. State Museum, 1912. 



