72 BRITISH FOSSIL CRUSTACEA. 



Ptertgotus Banksii, Salter. U. Ludlow Rock and Passage-Beds, Ludlow.Whitcliffe, &c. 



— tatjrinus, Salter. U. Silurian, Ewyas-Harold, Herefordshire. 



— ludensis, Salter. Old Red Sandstone, Ludlow, Trimpley, &c. 



— gigas, Salter. Downton Sandstone and Passage Beds, Kington, Hereford. 



— problematicus, Salter. U. Ludlow Rock, and Passage Beds, Whitcliffe, 



Ludlow Cornstones, Old Red Sandstone, &c. 



— arcuatus, Salter. L. Ludlow Rock, Church Hill, Leintwardine. 



— stylops, Salter. U. Silurian, Kington. 



With the exception of Pterygotus Banksii, they are founded upon well-marked fragments 

 only — which, however decisive as to their specific distinctness, need further confirmation 

 by the discovery of more perfect remains. 



Save in a few instances, therefore, it has not been thought desirable to redraw these 

 detached portions, but rather to refer the reader to the large series of remains figured in 

 the Geological Survey Monograph by Messrs. Huxley and Salter, and to reprint the 

 descriptions of species as given by the latter, 1 merely correcting any obvious errors and 

 making such few additions as we are enabled to do with confidence by our increased 

 acquaintance with the more complete examples from other localities. 



Should more perfect remains be discovered, as there is every encouragement to hope 

 may be the case, we may yet, at some future day, figure as entire examples of these West 

 of England Pterygoti as we have been enabled to do of those from beds of the same age 

 in Scotland. 



Species 4.— PTERYGOTUS BANKSII :— Salter. 1859. PI. XVI, figs. 2— 6. 



Himantopterus Banksii, Salter. Quart. Journ. Geol. Soc, 1856, vol. xii, p. 32 and 



p. 99, pi. ii, fig. 5. 



— — Siluria, 2nd ed., 1856, p. 266, foss. 66, fig. 1. 

 Ptertgotus Banksii, Salter. Mem. Geol. Surv., Mon. I, 1859, p. 51, pi. xii, 



figs. 22—46. 



— — Siluria, 3rd edit., 1859, p. 540. 



— — Ibid., 4th edit., 1867, p. 239. 



Named in honour of Richard Banks, Esq., of Kington, Hereford, who has made rich 

 collections of the Pterygoti of that locality. 



This small neat species, of which there are many specimens, both in the British 

 Museum and in that of the Museum of Practical Geology, occurs with Pterygotus gigas, 

 and spines both of Crustacea and fish, in the yellow tilestones 2 (Downton Sandstone) beds 



1 If we omit Eurypterus {Pterygotus) punctatus (which occupies nearly two folio plates, and has 

 twenty-eight figures devoted to its illustration), and Ft. taurinus (which was not published until 1868), tbe 

 six remaining species occupy four folio plates and are illustrated by ninety-seven figures ; all are in a very 

 imperfect state of preservation, and consist only of detached plates and appendages. — H. \V. 



2 Referring to this term the Rev. W. S. Symonds, M.A., F.G.S., Rector of Pendock, near Tewkesbury 

 (who has paid especial attention to the geology of this district), writes as follows : — " The word ' tilestones' 



