BRITISH FOSSILS. 53 



conical ones nearly straight, the central one as long as the width of 

 the shaft. In fig. 40, from the Ludlow Rock, the intermediate teeth 

 are a little longer in proportion. 



The basal joints, fig. 29, are flask-shaped, much more elongate 

 in the neck than those of H. bilobus, and less swelled at the base. 

 [It is possible they may not belong to the species at all, but to 

 Eurypterus linearis, a species which occurs in the same beds ; we 

 do not yet know this joint in Eurypterus.] The base is subqua- 

 drate, quite rectangular on the outer upper margin : the notch 

 for attachment of the other joints is immediately beneath this 

 angle, and tapering into the long neck, which has a sharp ridge 

 posteriorly, and together with the terminal lobe equals the length 

 of the basal portion. The teeth are minute. 



The post-oral plates, figs. 31 to 34, differ a little in shape from 

 figs. 41 to 44, but not specifically, unless the greater amount of 

 ornament in fig. 41 may be considered sufficient to separate it. The 

 shape is elongate oval, the greatest width at the upper third, the 

 base (6) subtruncate, the apex with a shallow obtuse notch. At 

 the lower fourth (a) is evidently a tubercle of attachment, and 

 such as occurs in a more linear shape in other species, Plate II. 

 fig. 4 a. [It is desirable to find out the post-oral plate of Euryp- 

 terus ; which is probably very similar.] 



The sculpture is very conspicuous over the upper half ; it consists 

 of nearly straight or very slightly curved plicae arranged in arched 

 lines and ending abruptly against the outer margin. In the sand- 

 stone specimens the sculpture does not extend so far down, but it is 

 identical in structure. 



Localities. UPPER LUDLOW ROCK, Ludlow Lane, Whitcliffe 

 (and Batchcot ? fig. 46) ; Parian, exterior slope of the Woolhope 

 "V 7 alley (Mus. P. G.) ; Kington, Herefordshire (Mr. R. Banks' cabinet). 

 PASSAGE-BEDS, Ludlow Railway cutting (Cabinets of Messrs. Light- 

 body and Marston, at Ludlow ; Museum Pract. Geol.), &Tc. 



