76 



Descriptions of New Species of Fossils. 



CRUSTACEA. 



ACIDASPIS FIMBRIATA 71. Sp. 



Fragments of a species of Acidaspis occur upon the surfaces of 

 some of the slabs which are mainly covered with Bryozoans. The 

 separated cheek pieces are distinguishable by the numerous straight 

 lateral spines which give them a fimbriate appearance. As many as 

 eleven of these lateral spines may be counted upon a single imper- 

 fect cheek. The border of the cheek is but slightly curved and the 

 long posterior spine is nearly straight. 



Ill^nus (Bumastus) Ioxus. 



lUcenus Ioxus Hall. 20th Rep. St. Mus. Nat. Hist., p. 378, plate 22, figs. 4-10. 

 1867. Revised edit., p. 420, pi. 22, figs. 4-10. [1870.] 



A large specimen of the caudal shield from the limestone, has all 

 the proportions of this species, though of somewhat larger dimen- 

 sions than is usual with the Wisconsin individuals. The specimen 

 measures 60 mm. in length, with a width of about 75 mm. 



In addition to the foregoing species the following known forms 

 have been recognized among the collections formerly and recently 

 made at Waldron: Buthotrephis gracilis, Orthis hiloha, Cypricar- 

 di7iia arata, Orthoceras sithcancellatum , and Orthoceras annulatum^ 



