L96 PALEONTOLOGY OF NEW YORK. 



has been somewhat distorted, and the test, which is extremely tenuous, 

 broken by compression in the shales. A single individual shows the im- 

 pression of the crown of a small mandible in the substance of the carapace. 

 This organ, in every visible feature, is comparable to those already described 

 under the species Eckinocaris punctata (page 167). The crown is curved or 

 lunate, and bears five denticles, of which the anterior is sharp and canine- 

 like, the posterior broader and more closely resembling the grinding surface 

 of a molar tooth. Its length is 5 mm. 



A.BD0MEN. In a single example the carapace is in close association with scat- 

 tered somites of the abdomen, of which three are detached and the fourth 

 is in articulation with the telson. One is quite broad, being twice as wide as 

 long and somewhat elevated in the middle, the margins very slightly ele- 

 vated ami faintly produced in the axial line; another is relatively longer but 

 quite imperfect; a third about one-half longer than wide, and the posterior 

 somite twice as long as wide, and nearly cylindrical. 



Post-aisdomen composed of a small caudal plate, whose entire dorsal surface is 

 occupied by the base of the telson, and is strongly elevated, the spine itself 

 being stout and sub-conical. The cercopods, in their normal condition, are 

 laterally flattened and slightly longer than the telson. 



The Sitrface of both abdomen and post-abdomen bears an ornamentation 

 of elevated, anastomosing and slightly undulating lines, similar to those upon 

 the carapace, but more conspicuous. These lines appear to be sharply angu- 

 lated along the axis of each somite, and directed thence posteriorly over the 

 lateral portions. 



Dimensions. All the carapaces observed are of about the same size. A 

 well-preserved individual measures 48 mm. in length including the prora, 

 which is 6 nun. long. The greatest width of one-half the carapace, as com- 

 pressed, is 10 mm. Of the abdomen one somite measures 5 mm. in length 

 and 10 mm. in width; another, 7 mm. in length and 5 mm. in width, and 

 the posterior somite Id mm. in length and 5 mm. in width. The telson is 

 L5 mm., and the cercopods each 17 mm. in length. 



