EURYPTERID REMAINS FROM THE PENTLAND HILLS. 587 



incisions. Of these the one nearest the apex is the best developed and marks off a dis- 

 tinct lobe. The other three are much smaller. 



The triangular plate, arising as usual from the posterior portion of the distal end of 

 the penultimate joint, is very large in this form. Its breadth at the base is 27 mm., and 

 the length must have been about 35 mm. It is larger in proportion to the last joint 

 than in any other Eurypterus with which I am acquainted. 



I have ascribed a fragment of tail spine (PI. IV., fig. 25) to this form. The chief 

 reason for placing it here is that it does not seem to belong to either of the large species 

 of Stylonurus. It had a triangular ridge running down the middle and occupying one 

 third of the width. 



In comparison with other species, Eurypterus scoticus seems most nearly allied to 

 E. scorpioides (Woodward) ; E. punctatus (Salter) ; E. (Eusarcus) scorpionis, G-rote ; E. 

 (Echinognathus) clevelandi (Walcott) ; E. acrocephalus (Semper). The last two may be 

 disposed of in a few words. E. clevelandi was founded on a single limb, which in struc- 

 ture shows a close resemblance to the Eurypterids of this type, being furnished with 

 long, curved spines. The number of spines is greater than in any of the usual forms, 

 and it is possible that more than one limb may be present. Of E. acrocephala only 

 the general shape of the carapace and body segments is known. These agree fairly well 

 with E. scoticus, the carapace being conical, and the body widening in the first few 

 segments and suddenly narrowing in the seventh. The remains of appendages in this 

 Bohemian form are too slight and indistinct to admit of comparison. 



E. punctatus of Salter resembles our form closely in some respects. The spine bear- 

 ing legs are, on the whole, similar, but the spines are, according to the description, 

 markedly striated. Further, the form of the swimming foot differs in the much greater 

 length in proportion to breadth of the terminal joint, and in the greater breadth of the 

 terminal joint in proportion to the penultimate one. E. scorpioides can be distinguished 

 by the proportionately shorter spines on the 3rd — 5th appendages, and by the less-marked 

 width of the swimming foot as a whole. The terminal joint of this foot in E. scor- 

 pioides is also of the same width as the penultimate, while the triangular plate on the 

 posterior side is very small. Eurypterus obesus resembles E. scoticus in the general 

 body form, but the anterior appendages do not seem to be furnished with spines, while 

 the last pair have a form more like E. remipes, the terminal joints being much ex- 

 panded. 



Eurypterus minor (PI. V., figs. 27-29). 



Carapace subquadrate, breadth slightly greater than length ; eyes oval ; body taper- 

 ing ; telson strong, triangular in section about equal in length to the last three segments ; 

 body surface granular. 



This is a small form, the type specimen (fig. 27) measuring only 74 mm. in length. 

 The specimen from which fig. 29 was drawn is somewhat larger, but wants the carapace 

 The carapace is widest at the posterior margin which is slightly concave. The sides 



