SALTEE EURYPTERTJS. 235 



E. chartariu&, lanceolatus, postice attenuatus, 14 unciam longus, capite obtuso 

 hemispliserico, quam corpore latiore ; thoracis articulis latis brevibus, abdo- 

 minis (etiam penultimo) transversis ; cauda brevi triangulata, acuta atque non 

 acuminata. 



The eyes are small ; the swimming-foot also small ; its two dilated 

 terminal joints, taken together, form an oblong palette, scarcely so 

 long as the head. 



Locality. — Lesmahago, Lanarkshire; in Upper Ludlow Eock (Mns. 

 Pract. Geol.). 



EuETPTEEUs ? ; pincers (antennae). PI. X. fig. 20. 



It is thought worth while to figure here the chelate extremity of 

 either Pterygotus or Enrypterus ; most probably the latter, since all 

 the species of Pterygotus of which we know the antennae have longer 

 chelae, well supphed with teeth ; these are, however, short and un- 

 armed ; and the fixed branch curves inwards, while the free joint is 

 a little recurved to follow it, after the manner of the piacers in 

 many recent Crustacea. The base is broad, short, and rhomboidal. 

 If it belong to JEurypterus (the antennae of which are known to have 

 short smaU chelae), it would probably be referable to the common 

 E. pygmceus, which occurs in the same beds. A very similar, but 

 much larger form is found in the Lower Ludlow Rock of Leint- 

 wardine. 



Locality. — Bone-bed (Upper Ludlow), of Ludford. Mr. Light- 

 body's cabinet. 



The distribution of the species of Eijeypteetjs, so far as yet known, 

 is as follows : — 



1. Eurjpterus? sp. Lower Ludlow Eock, Leintwardine. This is doubtful. 



2. E. Cephalaspis, Salter. Appendix, Brit. Palseoz. Foss. Woodwardian Mu- 



seum, Cambridge. PI. I E. fig. 21. Upper Ludlow Eock, Westmoreland. 



3. E. pygmseus, Salter. Upper Ludlow, Downton Sandstone, and Base of Old 



Eed Sandstone. Ludlow, and Kington, Herefordshire. 



4. E. Unearis, Salter. Upper Ludlow and Downton Sandstone, Ludlow. 



5. E. acuminatus, Salter. Passage-beds, base of Old Eed. Ludlow. 



6. E. megalops, Salter. Passage-beds, Ludlow. 



7. E. abbre\datus, Salter. Downton Eock, Kington, Herefordshire. 



8. E. chartarius, Salter. Uppermost Ludlow, Lesmahago, Lanarkshire. 



9. E. tetragonophthalmus, Fischer. L^ppermost Silurian beds. Island of 



CEsel, Baltic ; also in PodoUa. 



10. E. remipes, De Kay. Uppermost Silurian beds. WiUiamsville, Erie, Buffalo, 



U.S. 



11. E. lacustris, Harlan. (Physical Eesearches, p. 297, plate not numbered, 



fig. 2.) Same locaUty as that of E. remipes ? A distinct species from the 

 last. 



12. E. Symondsii, Salter. Old Eed Sandstone, Brecon. 



13. E. Scouleri ? , Hibbert. Upper Old Eed Sandstone, Kiltorkan, Kilkenny 



Co. (If this should prove to be a new species, it might be named E. 

 Forbesii ; for Prof E. Forbes first recorded its fragments from the fresh- 

 water beds of Kilkenny, where it is associated with Sphenopteris, Lepido- 

 dendron, Anodon, Coceosteus, and Dendrodus.) 



14. E. Scouleri, Hibbert. Lower Carboniferous. Fifeshire. 



The range of the genus, therefore, so far as yet known, certainly 

 is confined between the Ludlow Rocks and the base of the Carbonife- 



VOL. XV. PAET I. s 



