NAPLES FAUNA IN WESTERN NEW YORK, PART 2 347 



radials together bear a strong. arm, gradually tapering to a point, about 

 three times the length of the calyx. It is broad, flattened on the back and 

 longitudinally depressed along the center, and is composed of a double 

 series of very short plates, meeting at the center and arranged in opposite 

 (not alternate) order. 



On the outer and ventral side the arm bears long, slender, cordlike 

 branchlets, which appear to have fine threadlike appendages along their 

 sides. In the central part of the arm these branchlets are as long as the 

 arm itself. They proceed from every third arm plate, instead of every 

 fourth, as in M. bainbridgensis, and the plates from which they 

 appear are opposite each other, and their outer sides are lengthened 

 slightly. 



The interradials are apparently like those of M. b a i n b r i d g e n s i s, 

 beginning with a large plate between the upper parts of two adjacent 

 radials, followed above by two smaller plates, and these by more, still 

 smaller plates, the number or arrangement of which is not uniform. 



The calyx plates are marked by granulations over the central portion, 

 are rounded at the margins, which in some cases are elevated slightly above 

 the central part of the plate, causing a depression, as in M. b a i n b r i d g- 

 e n s i s ; other plates (even on the same specimen) are convex, as in M. 

 breviradiatus. The rows of fine ridges, connecting the calyx plates 

 at their juncture, are very distinct in some cases, and do not appear in 

 others. The former is a character of M. breviradiatus. 



The stems are composed of alternately thin and thick plates the rela- 

 tive order, or proportions, of which are not constant, even varying on the 

 same stem when preserved for long distance. 



This species is closely related to Melocrinus bainbridgensis 

 Hall & Whitfield, 1875, from the Huron shale, Bainbridge O., and to M. 

 breviradiatus Hall (figured on a plate of "New Crinoidea, plate 1," 

 which was published, with explanation of plates, in 1872), from the Ham- 

 ilton group. 



The study of the specimens (all on a single slab), from which the above 

 diagnosis is made out, has revealed the fact that apparently all the charac- 

 ters distinguishing the two species just named are variable in those speci- 

 mens. The arms must be excepted ; none are known for M. breviradi- 

 atus, and those described for M. bainbridgensis were not found 

 attached to any calyx.. 



While, therefore, we retain a distinct specific name for the specimens 

 under consideration, we are led to believe that examination of a larger series 

 of specimens may make it necessary to unite these three species in one. 



This species is interesting for its abundance in a thin limestone layer 



of the Genesee, which lies close above the Genundewa limestone, and con- 



