262 Forty-third Report on the State Museum. 



AOTINODIC^TYA PLACENTA, Sp. n. 



Retioulum usually longer in one diameter than in the other. Sur- 

 face generally somewhat elongate and convex, rarely flat; margins 

 usually without definition. The spicular bands cross the surface in 

 all directions, making polygonal meshes of various sizes. Bands of 

 different sizes are apparent, but they can not be satisfactorily divided 

 into primary and secondary series. Its surface is usually free of any 

 pronounced irregularities. This curious form appears to have crown in 

 broad, flabellate expansions over the sea-bottom, perhaps conforming 

 to the contour of other objects. 



As generally found, they have accumulated one above the other in 

 layers parallel with the plane of sedimentation. The largest fragment 

 observed has a length of 250 mm. and a greatest width of 85 mm. 



Formation and localities. — In the Chemung group, at Howard and 

 Cohocton, Steuben county, N. Y., and on a creek two miles above 

 Lawrenceville, Tioga county, Penn. 



Cbyptodictta gen. nov. 

 Irregularly growing, uninclosed (?) nodose or vesiculose forms com- 

 posed of a thick obscurely reticulate or non-reticulate plasma with very 



obscure spicules. 



Cryptodictya Alleni sp. n. 



Reticulum irregularly explanate, more or less convex generally 

 longer in one diameter. Where the margin is distinctly preserved it 

 appears to be usually incurved or abruptly deflected from the general 

 surface of expansion. The edges of this surface are usually bordered 

 by a series of prominent nodes, which are frequently the most con- 

 spicuous occurring on the fossil. These nodes are large or small, 

 frequently compound, scattered at irregular intervals over the surface, 

 sometimes approximating a regularity which gives to the species a 

 form sugg'estive of Dictyophyton tuberosum. The spicular bands are 

 very obscure but are sometimes distinctly seen near the margins as 

 fine subparallel lines. 



The great variety of form presented by this fossil indicates that, 

 with more complete material it may be possible to establish differences 

 of specific value, but the specimens at hand, though of considerable 

 number, do not justify such a separation at present. 



The largest example has a length of 225 mm. and a greatest width 

 of 130 mm. Essentially these proportions are retained in all nearly 

 entire individuals. 



Formation and localities. — In the Chemung sandstones at Cohocton, 

 Steuben county and Lyndon, Cattaraugus county, N. Y. Originally 

 discovered and collected by Rev. J. Allen of Alfred University, Alfred, 

 New York. 



