246 paljeontoloot of nkw-york. 



Fig. 2 a. Aa entire specimen, preserving the posterior spines of the buckler. 



Fig. 2 b. Front view of the same, showing the elevation of the oculiferous tubercles. 



Fig. 2 e. A small specimen with the surface markings obscure. 



Fig. 2 d. Lateral view of a specimen, showing the extension of the extremities of the lateral articulations. 



Fig. 2 e. Caudal shield of a larger individual. 



Fig. 3/ An enlarged portion of the buckler of 2 a, showing pustulose tubercles, which appear much 



like the tubercles on the surface of Echinus or Cidaris, for the attachment of the spines. 



The oculiferous tubercle, under an ordinary magnifying glass, presents only small un- 



arranged granulations. 

 Fig. 2 g. The caudal shield and a portion of the thorax enlarged, showing the tubercles upon alternate 



and third segments. 

 Fig. 2 k. Profile of the same. 



Position and locality. This rare species occurs in the lower shaly portions of the Trenton 

 limestone, being scarcely known except in the soft argillaceous beds, which admit of 

 their nearly perfect preservation. I am indebted to Mr. Wadleigh, of Middleville, for 

 several very good specimens. (.state Collection.) 



303. 4. CERAURUS? PUSTULOSUS. 



Pl. LXI. Figs. 2 a, b. 



The specimen is a fragment, apparently of the lower side of the maxillary shield, with 

 the prolonged posterior extremity. It is clearly distinguishable from the preceding species, 

 by the large pustulose markings with a finely granulated surface between. 



It is not easy to decide positively regarding this fragment, and further discoveries may 

 prove it to belong to the Genus .^cidaspis, which in its surface marking is allied to Ceraurus. 

 The margin presents some ejevated tubercles or fine lines which are not represented in the 

 figure. 



Fig. 2 a. The fragment, natural size. 2 6. A magnified portion of the same. 



Position and locality. This fragment was obtained from the higher beds of the Black- 

 river limestone, near its junction with the Trenton limestone, at Watertown. 



(From Dr. Crawk.) 



very Bimilar to the one under consideration, and the difference of geological position renders it desirable to point out 

 any differences of character. In the Dudley specimens, though not larger than ours, there are at least twenty-five 

 segments in the middle lobe and eight or nine in the lateral lobe, every fourth articulation is tuberculated, and the 

 tuberculations on the lateral lobes are nearer the axial lobe. The surface, also, appears not to have been as roughly 

 granulated as in the Trenton species. Hisinger cites Calymene punctata as from the more recent Transition 

 limestone, and Mcrchison has given it from the Caradoc sandstone. There are doubtless two species referred to this 

 name, and I have regarded the one under consideration as differing from the species of Wahlenberg, Dalman, 

 Itc., though closely allied to it. 



