300 J. Walter Gregory — On Rhynchopygus Woodii. 



IV. — On Rhykchopygus Woodi, Forbes sp., from the English 



Pliocene. 



By J. Walter Gregory, F.G.S., F.Z S., 



of the British Museum (Natural History). 



fCEINAEACHNIUS WOODI was founded by Forbes in bis 



_i_v 



" Monograph of the Echinodermata of the British Tertiaries 



" i 



on two fragments from the Eed Crag of Suffolk ; of all the species 

 described in that work, this has been regarded as the most interest- 

 ing and problematical. As this species certainly belonged to a genus 

 now foreign to the British or European seas, it was felt, that if 

 its correct generic position could be determined, it and Temnechinus 

 would indicate the true affinities of the Crag Echinoderm fauna, 

 better than the cosmopolitan genera with which they were associated. 



The material on which the species was based was, however, so 

 imperfect that Forbes prefaced his description by the remark, "It is 

 with much doubt that I refer the following fossils to this genus," 

 while he further admitted that it was not impossible that the two 

 fragments might belong to different species. Though subsequent 

 echinologists have expressed doubts as to the correctness of Forbes's 

 identification, they have accepted it provisionally, and on the strength 

 of it, Echinarachnius has been generally recorded as a Pliocene 

 genus ; otherwise it has only been found fossil in the Pleistocene 

 deposits of Japan and Patagonia. 



In spite of the fact that the diligent collectors of Crag fossils 

 had been stimulated by Prof. Forbes' exhortation to seek for even 

 the smallest fragments of this species, nothing was found that would 

 elucidate its true systematic position. The first advance was made 

 by Prof. A. Agassiz in his report on the Echinoidea collected by the 

 Challenger : J from the evidence afforded by Forbes' figures he 

 therein suggested that, while the more perfect specimen was probably 

 part of either a Rhynchopygus or a very flat Nucleolites, the other 

 (fig. Qb) belonged to a Pourtalesian, as " it has the peculiar snout 

 thus far known only in that group." 



Prominent attention was thus directed to the specimen as, had this 

 view been coi'rect, the fragment would have been the sole fossil repre- 

 sentative of the Pourtalesiadse. Prof. F. Jeffrey Bell, at the request of 

 Prof. Sven Loven, made a careful examination of the specimens, which 

 had then been acquired by the British Museum, but concluded that 

 they were too imperfect for any definite decision as to their affinities 

 to be made. Professors Loven and Bell however both agree that 

 " there seems to be no reason whatever for regarding it as having 

 been part of something like a Pourtalesia." 3 



While recently examining the collection of W. J. Lewis Abbott, 

 Esq., F.G.S., I found another fragment of the species, and as this 

 shows the structure of the anal area, it enables its generic position 



1 Palseontograph. Soc. 1852, pp. 12, 13, pi. ii. figs. 5 and 6. 



2 "Challenger" Reports, Zool. vol. iii. No. 1, p. 30, 1881. 



3 S. Loven, " On Pourtalesia, a Genus of Echinoidea," Kongl. Svenska Vetensk. 

 Akad. Handl. new ser. vol. xix. No. 7, p. 86, 1883. 



