REVISION OF PALEOZOIC STELLEROIDEA. 101 



ing the junction of the inner faces of the adambulacral plates, mark 

 the proximal and distal margins of the ambulacral plates. These 

 ridges do not cross at right angles to the median line, but include 

 between their proximal sides an angle of about 125. These ridges 

 indicate that the ambulacral and adambulacral plates were equal 

 in number, and that the former were united in pairs along a straight 

 median line rather than in an alternate right and left arrangement 

 along a zigzag line, as is shown in Dr. Hall's figures. The pores 

 described as being ' excavated in the posterior border of the ambu- 

 lacral plates and just within their junction with the adambulacral 

 plates' are not clearly shown on this specimen, although there are 

 irregular and inconstant markings at some of the points of the molds 

 of the lateral extensions of the groove. A series of pores near the 

 median line is indicated by a series of small rounded prominences 

 on each side of the median ridge and very close to it. These promi- 

 nences are opposite the lateral expansions of the groove, and one is 

 found on the mold of each ambulacral plate. The pores appear to 

 have perforations very near the edges of the plates, or excavations 

 in their margins." 



Abnormal development. Among the 400 specimens of this species 

 recently found near Saugerties, New York, there are a few indi- 

 viduals each with but four rays, though otherwise they appear to 

 be of normal development. This is the first discovery of a four- 

 rayed starfish in the Paleozoic. 



Formation and locality. In the Hamilton of the Middle Devonic 

 near Hamilton, Summit and Cooperstown, New York, Two sepa- 

 rated rays of apparently this species were found by the writer in the 

 lower third of the Hamilton near Bartletts Mills, south of Thedford, 

 Ontario. Two other fragments from the same locality are in the 

 University of Toronto (Walker collection, No. 1610H). The type 

 and other specimens are in the American Museum of Natural History, 

 one* is in Colgate University, another at Wesleyan University, and two 

 in Yale University Museum. 



Recently the New York State Survey collected in the Hamilton 

 sandstone at Mount Marion, near Saugerties, New York, over 400 

 examples of this fine starfish. They occur in a limited area and 

 are often found in association with Grammysia and in such manner 

 that Doctor Clarke believes the starfishes were feeding on the bivalves. 

 This is probably the most remarkable find of Paleozoic starfishes, and 

 is certainly so for America. 



DEVONASTER CHEMUNGENSIS, new species. 



Plate 11, fig. 2. 



Of this species only the actinal side is known, and its general 

 structure so far as can be made out is that of D. eucharis (Hall). 



