BUFFALO SOCIETY OF NATURAL SCIENCES 245 



proportions generally agree in the two species. Even more like 

 E. scorpionis is the single known specimen of E. obesus from the same 

 Lesmahagow horizon, and it has been suggested by Woodward, who 

 described the species, that E. obesus may possibly represent the young 

 of E. scorpioides ; certainly E. obesus looks very much like a young 

 individual of E. scorpionis figured by Clarke and Ruedemann from 

 the Bertie (Figs. 24 and 25). Thus there is close relationship 

 between the two species from Lanarkshire and the one from the 

 Bertie. 



The last species from the Ludlow fauna, and the only Eurypterus 

 yet found therein is E. lanceolatus Salter. As Sarle, Clarke, and 



Fig. 24. Eurypterus obesus H. Wood- Fig. 25. Young or Eusarcus scor- 



waed. X ttj pionis Grote and Pitt. X \ 



(After Woodw. 1878, pi. XXX, fig. 8) (After C. & R. 191 2, pi. XXXVI, 



Ruedemann have pointed out, this species has many points in com- 

 mon with Hughmilleria and either belongs to that genus or is transi- 

 tional to it. The form of the body, shape of the carapace and of the 

 telson, marginal position of the eyes, the relative proportions of the 

 somites, and details in the appendages, all point to affinities with 

 Hughmilleria socialis Sarle, from the Pittsford (figs. 26, 27). Such 

 a relationship seems a little disconcerting at first, in view of the 

 fact that the Pittsford sediments and fauna came from Appalachia, 

 while the Ludlow was a derivative from Atlantica and should have a 

 fauna essentially distinct from the former. Indeed, with the excep- 

 tion of this one species, the members of the Ludlow fauna show no 

 relationship to any species from the faunas of Appalachia. We 

 have here, as a matter of fact, one of the " anomalies" of distribution 



