A MONOGRAPH 



OF THE 



BRITISH FOSSIL CRUSTACEA 



OF THE 



OEDEE MEROSTOMATA. 



PART III. 



Genus 1. — Pterygotus, Agassiz. — Continued. 

 Species 3.— PTERYGOTUS RANICEPS :— H. Woodward. 1868. PI. XVI, fig. 1. 



Pterygotus raniceps, H. Woodward. Quart. Journ. Geol. Soc, 1868, vol. xxiv, 



p. 294, pi. ix, fig. 3. 



Our knowledge of this species is confined to a single specimen obtained, like the 

 preceding one, by Mr. Robert Slimon from the hard flaggy shales (Upper Silurian) of 

 Logan Water, near Lesniahagow, Lanarkshire (see pages 46 — 52). 



Head-shield obtusely triangular. Eyes prominent, marginal. Breadth of posterior 

 border of carapace 6 lines; greatest length 4^ lines, from posterior border to eyes 3 

 lines ; breadth of carapace at eyes 3^ lines ; diameter of eye 1 line. 1 A small depression 

 marks the centre of the carapace between the eyes, and a small elevation may be seen 

 slightly posterior to them, also on the median line. Larval eye-spots not visible. Length 

 of the six segments 1\ lines, greatest breadth 9 lines ; no ornamentation is preserved 

 upon any part of the integument. 



The specimen here described and figured is preserved in the British Museum. 



REMAINS OE PTERYGOTUS FROM THE WEST OE ENGLAND. 



The following seven species 2 are given upon the authority of Mr. J. W. Salter, the 

 late eminent Palaeontologist to the Geological Survey, who had devoted many years to 

 the investigation of this group ; namely : 



1 This tubercle probably marks the position of the ocelli. 



2 An eighth species, Pterygotus punctatus, Salter, has, since its publication, been determined to belong 

 to the genus Eurypterus (see ' Quart. Journ. Geol. Soc.,' 18G8, paper by H. Woodward, " On some New 

 Species of Crustacea," &c, vol. xxiv, p. 290, plates ix and x). 



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