440 R. I. Pocock — On Eophrynus and Allied Arachnida. 



Thirty-five years later a second and remarkably perfect specimen 

 of C. Tprestvicii, which set at rest the question of the Arachnidan 

 affinities of the species, was discovered in the clay ironstone of 

 the Dudley Coal-measures. Upon the species represented by this 

 specimen Dr. Woodward based the genus Eophrynus, leaving ansticii 

 by elimination as the type of Curculioides. 



Unfortunately, owing to certain errors committed by the artist, 

 the figure and description of the fossil are discrepant in various 

 particulars. In other cases important structural points are obscured 

 by heavy shading. These blemishes in the illustration made the 

 subsequent determination of the true structure and taxonomic position 

 of Eophrynus a matter of considerable difficulty. A far more accurate 

 figure was subsequently drawn by Miss G. M. Woodward, under 

 Dr. Woodward's supervision, and printed in the "Guide to the 

 Fossil Invertebrata in the Department of Geology and Palaeontology 

 in the British Museum" (Natural History), 1897. I am indebted 

 to Miss Woodward for the care and skill shown in the preparation 

 of the figures accompanying Part II of this article, which were 

 taken partly from my sketches representing my conception of the 

 features exhibited by the fossil. Since the cast of Eophrynus is 

 the only representative of this group of Carboniferous Arachnida 

 that I have been able to see, I have been compelled to trust to 

 the accuracy of the figures and descriptions of other authors for 

 information regarding allied forms. 



The subject-matter of this essay may be conveniently divided into 

 three sections: (1) The morphology of Eophrynus; (2) the classi- 

 fication of Eophrynus and its allies ; (3) the taxonomic position of 

 the Anthracomarti. 



1. The Morphology of Eophrynus. 



The synonymy of Eophrynus prestvicii is as follows : — 

 Eophrynus prestvicii (Buckl. sp.). 



Curculioides prestvicii, Buckland: Bridgw. Treatise Geol. and Mineral., vol.ii (1836), 



p. 76, pi. 46", fig. 2 (2nd edition, 1837). 

 Eophrynus prestvicii, H. "Woodw. : Geol. Mag., 1871, pp. 386-388, PI. XI ; and 



of subsequent authors. 



The carapace is unsegmented. It is narrowed anteriorly, its 

 posterior width exceeding its length. Its median area from the 

 anterior almost to the posterior border is raised into a broad 

 longitudinal axial elevation, divided superficially into ridges and 

 lobes by transverse and longitudinal grooves. Two transverse 

 constrictions which cross its dorsal surface divide it into three 

 subequal portions — an anterior, a median, and a posterior. The 

 last is laterally crested and impressed mesially and behind by 

 a longitudinal groove, which appears to correspond to the median 

 muscular impression or fovea present upon the carapace in some 

 other orders of Arachnida. The median and anterior portions are 

 divided by two longitudinal grooves into a central and two lateral 

 crests. The central crest of the median portion is the highest point 

 of the carapace. It bears a pair of oval pits. The anterior portion 

 slopes obliquely downwards and forwards to its narrowed but bluntly 



