Description of Two JSfeic Genera and Eight New Species. 39 



bases and roots interlocking and attaching to supports, in such man- 

 ner, as to indicate that it was, at all periods of life, a stationary 

 crinoid. 



Immediately above the roots, the column is round and smooth, next 

 we observe that it is longitudinally divided into five parts, and then 

 longitudinally fifteen partite, with a large, rayed, pentagonal, central 

 opening. The truncated ends of the rays each abut upon one of the 

 longitudinal parts, and two of the longitudinal parts fill each of the in- 

 terspaces. At another part of the column it is composed of twenty 

 longitudinal rows of plates, three of which occur between the ends of 

 the ra} r s and one at each of the ends. Each longitudinal part or row of 

 plates consists of an alternate arrangement of three, four, or five thin 

 plates, followed by a thick projecting plate. This structure forms a tuber- 

 culated column, the tubercles being arranged in longitudinal and 

 transverse order. Near the head the tubercles are less conspicuous 

 than below. 



The interior of the column may be described as follows : The spaces 

 between the rays of the opening consists, in each instance, of a smooth 

 angular projection or ridge composed of numerous plates, while the 

 intervening spaces or the rows of plates that abut upon the ends of the 

 rays of the opening are not smooth, but consist of alternately pro- 

 jecting pieces which make each space as rough as the exterior. 



The column is the largest known from the Hudson River Group, and 

 much the most complicated in its organization. The specimens il- 

 lustrated are from my own collection, and f found them near the 

 top of the hills within the city limits. 



Stomatopora proutana, n. sp. 



Plate I., fig. 4, slightly enlarged; 4a, magnified view; 46, magnified many diameters. These 



views are only approximately correct. 



Potyzoary creeping, adhering its whole length to other objects, and 

 branching at irregular distances. Each branch arises as a delicate 

 line in front of and below the preceding swollen cell, and where two 

 branches arise from below the same swollen cell, their angle of bi- 

 furcation varies from 10 to 90 degrees. The branches enlarge verv 

 little, if any, for the distance of about half a line, when each gradually 

 expands into a subpyriform termination, containing a single cell mouth. 

 The distance between the subpyriform expansions varies from three to 

 six times the length of each, and the greatest diameter of the expan- 

 sion is only about twice as. great as the diameter of the branch below. 



