New Orders and New Families in the Class Echinodermata. 227 



Brachials. — There are three brachials, or free radial plates, support- 

 ing arms, in each of the five series. The first plate is longer than 

 wide ; it is longer than any plate in the calyx ; it tapers very gradu- 

 ally, and being round upon the outer face presents the appearance of 

 a truncated cone. The second plate is rather wider than long, and 

 tapers less, proportionally, than the first. The third plate is penta- 

 gonal, rounded, expanded at the upper third, where its width is about 

 equal to the greatest length, and supports the arms upon its upper 

 sloping sides. This description will apph' to three of the series, but 

 the two series upon the azygous side are a little narrower at the base 

 of the first brachials, and therefore taper less in the first and second 

 plates. 



Arms. — There are ten arms, rather stout, and of medium length. 

 They are composed of elongated, somewhat wedge-shaped, plates, that 

 project slightly at the upper margin of the longer sides from which the 

 pinnules arise, giving the arms a serrated or roughened aspect upon 

 either side. The pinnules are long and strong. None of them in the 

 illustrations are drawn to their full length, and the plates are longer 

 than they are indicated in fig. 4c, which was drawn rather to indicate 

 a magnified piece of an arm than to show the appearance of the 

 pinnules. 



In terra dials and 2^'oboscis. — There are two or three small plates 

 upon the azygous side, within the calyx, which seem to belong to the 

 ventral tube or proboscis, which are succeeded by small plates that 

 cover the proboscis, as shown in the magnified view, fig 4£>. The pro- 

 boscis is large, separates widely the two anterior arms, and gently 

 curves inward between the arms and pinnules. It is shown broken off 

 in fig. 4. It appears that it extended, in height, beyond the arms. 



This is a marked and beautiful species, that will not be confounded 

 with an}' other known to the author, who collected it, in rocks of the 

 age of the Upper Helderbcrg Group, at Deputy, Indiana. 



The specific name is in honor of William J. Davis, author of the 

 " Fossil Corals of Kentucky," in the forthcoming volume of the 

 Palaeontology of that State, who has been making his home, for many 

 years, in the special interest of palaeontological science, among the 

 Devonian fossils in the vicinity in which this species was collected. 



POTERIOCRINUS NETTELROTHANUS, n. Sp. 

 [Plate IX., fig. 5, enlarged two diameters ; fig. 5a, magnified view of two arms as they 



appear from the fourth brachial.] 



This species is very small, column comparatively large, and aims 

 remarkable for unequal bifurcations. 



