228 



PALJEONTOLOOy OF NEW-YORK. 



602. 1. I\IELOCRINITES SCULPTUS. 



Pi.. XLIX a. Fig.2a-d. 

 Compare Melocrinites lavis, Goldfuss, ut supra, pi. 60, fig-. 2. 



Base concave ; column round ; articulating surfaces of joints strongly striated ; stride 

 reaching nearly or quite to the canal ; pelvic plates spreading outward and downward, en- 

 closing the column, and having their surfaces marked by a few concentric lines ; costal plates 

 five, bending slightly downwards to their centre, from which point they are suddenly bent 

 upwards ; surface of costal plates marked only by concentric lines or ridges ; costal plates, 

 at the point of bending upwards, marked by a strong angular node on each side, and below 

 this an eipially prominent one in the centre of the plate ; near their upper margins these plates 

 are each marked by three prominent sharply angular ridges, which probably corresponded to 

 similar ones on the succeeding plates. 



This crinoid, when held in a reversed position, has a coronate appearance, from the promi- 

 nent angular nodes on the margins of the costal plates. The base of the pelvic plates is 

 depressed below these angles to the depth of three eighths of an inch. This feature contrasts 

 very strongly with the narrow protruding base of M. hieroghjphicus ; and there is in the figure 

 of M. IcEvis no appearance of a depression at the base, though the upper margins of the first 

 costal plates of our specimen are marked in a manner very similar to that species. 



Fig. 2 a. View of the base of thii species, showing the plates slightly separated. 



Fig. 2 i. A figure showing the structure and relative position of the plates. It will be seen by this 

 figure, that if the pelvic plate on the upper side were divided, it would make two 

 of the same form as the other three. This structure of the base clearly arises from a 

 development of a single plate in place of two, accompanied also by a slight modifi- 

 cation of the adjoining pelvic plates in the extension of their sloping sides. 



Fig. 2 c. The interior of a cup which is much elevated in the centre, showing an exterior de- 

 pression corresponding to the specimen described. In this fragment the divisions of 

 the plates are not conspicuous, and it may possibly prove a distinct species. 



Fig. 2 d. The articulating surface of a joint of the column, attached to the specimen fig. 2 a. 



Position and locality. This species, of which only the fragments figured are known, was 

 found in the lower part of the Niagai-a limestone at Lockport. {Collection of Col. Jewett.) 



