21 



slender processes like those figured by Professor Hall for E. lacustris 

 in the Palaeontology of New York, Vol. III., Plate 81, Figs. 6 and 7. 



7. All the above described fossils have been collected from the 

 water-lime group near Buffalo, on the grounds of the Union Cement 

 Company, Mr. U. Cummings, superintendent, to whose liberality 

 the museum is indebted for a large number of specimens. P>esides 

 these, Eurypterus remipes, lacustris, rooustus and dekayi have been 

 recently collected from the same locality. All can be easily identi- 

 fied by the excellent figures given in Professor Hall's works. The 

 only one of all hitherto described Eurypterii from the water-lime 

 group which is missing in our collection is Eurypterus pustulosus, 

 Hall, of which a single carapace has been found. A comparison of 

 the Eusarcus scorpionis, Grote and Pitt (B. B. S. N. S., Vol. III., 1), 

 with a large number of Eurypterii, shows that there does not exist 

 difference enough to admit the formation of a new genus; and I am 

 inclined to think that the finding of more complete specimens will 

 eventually show that Eusarcus scorpionis is Eurypterus pustulosus. 

 The careful study of all the material from the water-lime group in 

 the museum enables me to make a few corrections to the published 

 description of Eusarcus scorpionis. 



The type is not the ventral, but the dorsal side, with the exception 

 of the carapace. The specimen is remarkably contorted, the 

 whole body curved backward, a position not found in any other 

 specimen. The shape of the carapace cannot be given because it is 

 broken off along the line of the cephalic shield in both our speci- 

 mens; but there is no disconnection of the cephalothoracic portion 

 and the body, a fact clearly demonstrated by the chipping away of 

 some of the overlaying matrix. The impression of one swimming- 

 foot is not very distinct, but seems to accord more with Dolichop- 

 terus than with Eurypterus in structure, although it is not quite as 

 long. The narrowing of the thoracic segments is not so remarkable 

 after the matrix has been removed and a part of the carapace is vis- 

 ible; there is certainly no more difference in the shape of the body 

 between this species and Eurypterus dekayi, than there is between 

 the latter and E. re7iiipes. The widening of the terminal segment 

 described is due to the careless cutting away of the stone in which 

 it was imbedded; the other specimen of the same species shows no 



