568 Contributions to Invertebrate Palaeontology. 



Ecliiuocaris multiuodosa. 



Plate XII, fig. 10. 



Echinocaris multinodosa Whitfield, Am. Jour. Sci. and Arts, 3d series, vol. 19, 

 p. 38, 1880. 



Carapace elongate-subovate, about twice as long as high, rounded in front 

 and somewhat pointed behind ; the basal-line straightened along the middle 

 portion and parallel to the liinge-line ; cardinal line straight and nearly half 

 as long as tlie length of tlie valve, and a little nearer the anterior than to the 

 posterior end of the carapace. Margin of the valves bordered by a narrow, 

 elevated, thickened rim, which is expanded considerably in width around the 

 anterior end of the valve, and terminates in a rounded, elongated ridge at the 

 posterior extremity of the hinge ; from which point the ridge is directed 

 obliquely forward and slightly downward from the caudal line. The surface 

 of each valve is divided into three slightly elevated areas, with depressed sulci 

 between ; an anterior, a central, and a posterior one. The first is situated in 

 the middle of the anterior end of the shell ; the central one unites with the 

 anterior one below, and extends along tlie basal margin behind, in a narrow 

 curved point below the posterior one, and projects upward near the centre of 

 the valve in a triangular form, terminating in an elevated point just above the 

 median line. The posterior and largest area is ovate in form, and occupies 

 a little less than one-half the length of the shell, is narrowed in front and 

 pointed behind, taking the form of the extremity of the shell. The centre of 

 the anterior area is slightly tumid. Along the hinge-line and just below its 

 margin there are three subangular tubercles or nodes, at nearly equal dis- 

 tances and of neai-ly equal strength, except that the posterior one is prolonged 

 at its base into a low, rounded, and slightly curved elevation, which extends 

 to near the point of the central raised area before mentioned. These three 

 nodes, together witli the oblique ridge-like one terminating the marginal rim, 

 border the hinge-line on each valve. General surface of the valve finely 

 punctate, but most distinctly so on the posterior field. 



The elongated form of the carapace readily distinguished this 

 from any of the other species described, while the number of node- 

 like ridges is a very marked feature. The abdomen and telson of 

 this species have not been observed, although several imperfect 

 carapaces, mostly showing parts of both valves, have been obtained. 



Formation and Locality. — In calcareous concretions in the Erie 

 shales, at Leroy, Lake Co., Ohio. 



DECAPODA. 



Associated with the specimens of Entomostraca, described from 

 the concretions of the Erie shales of Ohio, are the remains of a 



I 



