9G 



ART1GULATA. 



pair were dilated into paddles. The basal joints of the first four performed the 

 work of mastication as in the King-Crab. This specimen was found in the Wa- 

 terlime Group (Upper Silurian), Williainsville, Erie Co., N. Y. 



Size, 9x9. Price, §1.50. 



No. 368. Euryptems laCHStris, Harlan. 



This specimen, from the same locality, is of medium size, and lies with the 

 dorsal side exposed. The carapace has been detached. The body is curved, and 

 the tail directed forward. Size, 7x6. Price, §1.00 



No. 369. Emypteras remipes, De Kay. 



The carapace of this species is more attenuated, being about three-fourths as 

 long as wide, and the tail-spine is somewhat slender and triangular in form. 

 From the same locality as the two preceding. Size, 13 x 10. Price, i$2.2o- 



No. 370. Fterygotus acuminatas, Salter. 



This genus was established by Prof, Agassiz in 

 1844. It derives its name from the peculiar charac- 

 ter of its foot-jaws, which, from their scale-like sculp- 

 ture, were at first mistaken for the remains of a Fish. 

 Like the Eurypterus, the P. may be described as a 

 " lobster-like Crustacean," since it has an elongated 

 body composed of a cephalo-thorax, an abdomen with 

 a dozen segments, and a tail-plate. It differs from the 

 Eurypterus, in having a less number of joints in the 

 feet, in the eyes being marginal, and in the large size 

 of the antennae. This fine specimen was discovered 

 in the-Upper Silurian beds of Lesmahago, Lanark- 

 shire, Wales. Size, 24 x 13. Price, $3.75. 



No. 371. Fterygotus acuminatus, Salter. 



This specimen shows well the singidarly square form of the head-shield and 

 the marginal position of the eyes on its anterior border. From the same local- 

 ity as the preceding. Ori-inal in the private Geological Cabinet of Mr. Ward, 

 Rochester. Hize,Q^. Price, $0.60- 



No. 372, Fterygotus Anglicus, Agass. 



Body. Segments asd Tail. This species— one of the 

 forms upon which the genus was founded— is the largest of 

 known Crustaceans, either living or extinct, A proportionate 

 completion of the entire body woidd give an animal of from 

 seven to eight feet in length ! The original, from the Old Red 

 Sandstone of Sidlaw Hills, Forforshire, Scotland, is in the Brit- 

 ish Museum. Size, 2 ft. 7 in. x 12 in. Price, $3.25. 



