154 MR MALCOLM LAURIE ON SOME EURYPTERID REMAINS FROM THE 



probably belong to this species, though they differ from the usual form of telson in 

 Stylonurus in tapering to a point. 



The metastoma is comparatively long and narrow, with a deep groove down the 

 centre. The posterior margin is straight or slightly incurved, about 12 mm. in length, 

 and ending in sharply rounded corners. The sides are slightly curved, and run almost 

 parallel to each other. The anterior margin is not seen in any of the specimens^ 



The only appendages preserved are a pair of long narrow legs on each side, one of 

 which is seen in situ in fig. 1, and another, the best of a number of detached fragments, 

 is drawn in fig. 6. ' The bases of these limbs, one of which is outlined in fig. 7, appear 

 to have been of about the same size, so that there would be two pairs of " ectognaths." 

 They are similar in general shape to the ectognaths of Pterygotus or Slimonia, and bear 

 five strong conical teeth along the biting margin. The postero-external angle is sharp 

 and almost rectangular, and the surface, especially of the posterior part, is closely 

 covered with angular scale- markings. The mode of attachment of the limb and the first 

 joint of it are not shown. The five distal joints of the limb are marked by a strong 

 longitudinal ridge. They decrease regularly in breadth, and vary considerably in length, 

 the antepenultimate (5th) joint being the longest, a point in which they differ markedly 

 from most other genera of fossil Merostomata. The measurements of the limb in fig. 7 



are as follows : — 







No. of Segment. 



Width. 



Length. 



3rd, 



18 mm. 



? mm 



4th, 



15 „ 



24 „ 



5th, 



11 „ 



40 „ 



6th, 



10 „ 



21 „ 



7th, 



8 „ 



20 „ 



The margin of the limb shows in places an obtuse crenulation (fig. 6a), and this probably 

 existed along the whole length of the posterior margin. The penultimate joint bears a 

 spine about 6 mm. long, inserted on the outer side of its articulation with the last 

 segment. The last segment tapers to a point. No trace of ornamentation is seen on the 

 appendages. 



This species, which I have ventured to name ornatus on account of the variety and 

 abundance of the ornamentation, differs from S. Logani in size and in the form of the 

 carapace, as well as in many minor points. The shape of the carapace and the position 

 of the eyes distinguish it from most of the Old Eed Sandstone forms. From S. Powrei 

 it differs further in the possession of epimera on the metasomatic segments and in the 

 form of the limbs. 



Stylonurus macrophthalmus, n. sp. (PL II. figs. 9-11.) 



This species is considerably smaller than the preceding one, the length of the whole 

 animal, minus the telson, being only 130 mm. The carapace is 37 mm. long and horse- 



