108 DiCTYOSPONGIDiE. 



nodes failing to appear at their proper position. The upper portion of the 

 cup is somewhat distorted from accident and the mending of the net-work. 



The reticulum is similar to that in H. tuberosum. 



Dimensions. This specimen has a length of 125 mm., which is nearly the 

 original extent of the sponge. At the lower extremity its width is 13 mm. 

 Where broadest, the width is 36 mm. 



Locality. Lower Chemung sandstone. Brown hill school house, near 

 Wallace, Steuben county. (Collection of E. B. Hall.) 



Hydnocebas variabile, sp. nov. 



Plate xxxvi, Fig. 1 ; Plate xxxvii, Figs. 4-6. 



Sponge of moderate size ; expanding slowly from the base for one-third or 

 nearly one-half of its length, thence upward widening more abruptly over the 

 node-bearing surface. The form is thus somewhat more slender below than 

 in other species and is further characterized by an apparent absence of nodes 

 over the basal region, or if not altogether absent their existence is only sug- 

 gested here and there. Normally there appear to have been not more than 

 three horizontal rows of nodes over the expanding portion of the cup. In 

 all the internal casts representing the species these are low and the full num- 

 ber, eight, is seldom developed. Fragments of the lower parts of the cup are 

 so nearly free of nodes as to fail to even suggest the genus Hydnoceras. Yet 

 when a specimen is retained in its matrix, as shown in figure 1, on Plate xxxvi, 

 this apparently anodate basal surface is found to have borne sharply defined 

 nodes nearly to the apex. As ordinarily preserved the specimens are very 

 variable in their general aspect, not only on account of irregularity of appear 

 ance in the nodes but also because of the irregular expansion of the reticulum. 

 The fundamental prism-faces are almost wholly obliterated even on the basal 

 portions of the cup. 



Reticulum. The net-work appears on internal casts to be coarse, on 

 account of the predominance of the secondary spicular bands forming meshes 

 measuring about 2 mm. on each side. The general aspect of the reticulum is 

 a composition of such rather coarse meshes, but these are more or less dis- 

 tinctly subdivided. 



Dimensions. A specimen, the most nearly entire of any observed and 

 having the nodes well developed, is 125 mm. in length and probably its origi- 

 nal length was not less than 140 mm. At the lower end its width is 30 mm.; 

 its greatest width 65 mm. 



