13 



than the second, pentagonal, axillary and bear upon each superior 

 lateral side two secondary radials. The secondary radials are 

 short, the last one axillary and supporting on each superior slop- 

 ing side three tertiary radials. This arrangement gives to the 

 species twenty arms and twenty am bulacral openings to the vault. 

 The ambulacral openings are directed horizontally. 



The regular interradial areas are depressed and flattened below 

 the base of the radial ridges. Some of the matrix covers the 

 plates in some of the areas so that they cannot be distinguished. 

 In the area, on the left of figure 13, there are three plates, one 

 in the first range and two in the second, one of which is much 

 longer than the other. In the azygous area there are five plates. 

 The first one is in line with the first primary radials, only about 

 half as wide but somewhat longer than either one of them. It 

 appears to stand up on the circular disc filling the middle part 

 of the depressed and flattened area. It bears a small central 

 tubercle, but all the other iuterradials are flat and smooth. It is 

 followed by three rather large flat plates, in the secoud range, and 

 above these, in the third range, there is a single, narrow, elongated 

 plate that extends one angle high between the second tertiary 

 plates, but is cut off from reaching the plates of the vault. 



Vault very high, conical, larger than the calyx and bearing a 

 large subcentral proboscis. The interradial areas are depressed 

 between each pair of arm bases. The vault is covered with large, 

 polygonal, and tumid plates, each one of which bears a large 

 ceutral node. There is a narrow elongated plate between each 

 pair of ambulacral furrows and an orifice at each of its inferior 

 angles. This arrangement places one pore on one side of each 

 arm or gives to the species twenty of these so-called ovarian 

 apertures. 



The large round basal disc, pentagonal outline of the calyx, 

 sharp radial ridges, depressed and flattened interradial areas, 

 conical vault and twenty arms distinguish this species. There is 

 no doubt but that the probossis is large and long and that the 

 basal disc is expanded, probably, beyond any other known species. 

 Both of these characters are ascribed to Eretmocrinus, but there 

 is no difficulty in showing, as we have before remarked, that the 

 proboscis, alone, cannot be relied upon to distinguish the genera. 

 The basal plates cannot be relied upon, for you may pass by a 

 graded scale from the extraordinary basals, in this species, to those 

 in Batocrinus wetherbyi and then to Batocrinus curiosus and then 

 to Batocrinus casula where the basals are rounded instead of ex- 

 panded. The only other character by which Eretmocrinus is dis- 



