On Certain Fossils of the Water-Lime Group near Buffalo. 



BY JULIUS POHLMAN. 



i. Pterxgotus Buffaloensis n. sp. The specimen consists of an 

 almost complete swimming-foot of this rare crustaceae. (Fig. i.) 

 The maxilliped has a breadth 

 of Tig inches, length of the 

 whole specimen 6J4 inches. 

 The surface of the first and 

 the edges of the second, 

 third, fourth and fifth joint 

 are covered with small, 

 rounded, scale-like process- 

 es, the other parts are finely 

 granulose. Professor Hux- 

 ley gives to his figure of 

 Pterygotus, reproduced by 

 Profess or Hall, in the Pale- 

 ontology of New York, Vol. 

 III., 424, a seven-jointed, 

 swimming • foot. But this 

 specimen shows the seven 

 joints down to the palette 

 very distinct, and another 



fragment of the same species has all the joints from the second 

 to the seventh inch entire, together with the soldered suture 

 line (Fig. 2.), which is so plainly seen in the Euryptej-ii. 

 We can, therefore, conclude that either Professor Hux- ( 

 ley's figure is wrong, or that the English Pterygotus dif- I v j 

 fers from the American genus, the number of joints 

 in the swimming-feet of the latter corresponding with 

 those of Eurypterus. 



Another fragment, which I for the present refer to 

 the same species, consists of one of the chelate an- 

 tennae. (Fig. 3.) The articulating extremity is well 

 defined, widening a little towards the place where 



x % 

 Fig. 2 



BUL. BUH. SOC. NAT. SCI. 



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