PLATE XXVIII. 



SILURIAN AND DEVONIAN CRUSTACEA. 



Order — Merostomata. 



Sub- Order — Eurtpterida. 



Figs. 



1 — 3. Eurypterus lanceolatus, Salter. 



Uppermost Silurian ; Lesmahagow, Lanarkshire. Drawn of the natural size. (F. 140.) 



1. The largest specimen obtained. One of the great swimming-feet (ectognaths) and about four of the 

 endognathary palpi are seen lying close to the borders of the head-shield. The impression of 

 the long median appendage of the thoracic plate is also seen underlying tlie 4th and 5th 

 thoracic somites. (P. 142.) 



2 has both the swimming-feet preserved and the thoracic plate (fig. 2 a) displaced, so as to show its form 

 completely. In this specimen the median thoracic appendage is short, bifid, and divided into 

 three joints. (P. 143.) 



3. The smallest example of E. lanceolatus obtained. (P. 143.) 

 Figs. 1 — 3 are preserved in the British Museum. 



4. Eurypterus Brewsteri, H. Woodw. (P. 151.) 

 Head-shield and ovisac ; natural size. 



Old Red Sandstone ; Kelly Den, near Arbroath. 

 Coll. James Powrie, Esq., F.G.S., lleswallie, Forfar. 



5. 6, 7. Eurypterus pygmccus, Salter. (P. 144.) 



Fig. 5. Head-shield, thoracic segments, and swimming-foot (nat. size). 



Downton Sandstone ; Kington. 



Coll. R. Banks, Esq., F.G.S., Kington. 

 Fig. 6. Head-shield, body-joints, and telson (nat. size). 

 Fig. 7. Body-joints and telson (nat. size). 



Basement-beds of the Old Red Sandstone ; Ludlow. 



Coll. Robert Lightbody, Esq., F.G.S., Ludlow. 



8. This series of body-segments are referred by Mr. Salter to Eurypterus (now Stylonvrus) megalops ; 



but the telson is broader and shorter than is usual in Stylonurus. (P. 146.) 



9. Another telson referred to the same species. 



Base of the Old Red Sandstone ; Ludlow Railway. 

 Coll. R. Lightbody, Esq., F.G.S. 

 10 — 14. A series of detached telsons or tail-spines of Eurypterus, described by Mr. Salter. 

 Figs. 10— 12. E. linearis, Salter. (P. 147.) 



Fig. 10. Upper Ludlow Rock; Ludford, Kington. 

 Figs. 11 and 12. Downton Sandstone; Kington. 

 Fig. 13. E. acuminatus, Salter. (P. 146.) 



Passage-beds, base of the Old Red Sandstone ; Ludlow Railway. 

 Fig. 14. E. abbreviatus. (P. 148.) 



Downton Sandstone ; Kington. 



15. Body-segments doubtfully referred to E. acuminatus. (P. 146.) 



16, 17, and 17a. Eurypterus Hibernicus, Baily. (P. 148.) 



Upper Old Red Sandstone ; Kiltorcan, Co. Kilkenny. 

 Museum Geol. Surv. Ireland, Dublin. 

 [Figs. 5 — 17 copied from the Plate illustrating Mr. Salter's paper. See 'Quart. Journ. Geol. Soc.,' 



1859, vol. xv, p. 232, pi. x.] 



