106 DlCTYOSPONGID^. 



Localities. In the schistose Chemung sandstones, on the farm of Thomas 

 Cotton, near Avoca, N. Y. Associated with this species here are great numbers 

 of a coarsely meshed sponge, probably H. tuberosum, which is always poorly 

 preserved ; also, // muUinodosum, Arystidictya elegans, A. nodifera and 

 HaUodidya Cottoiiiami. Reference has already been made to the probable 

 presence of this species in the Portage group at Varysburg, Wyoming county 

 (page 70). 



Hydnocebas multinodosum, sp. nov. 



Plate xxxix, Fig. 1. 



Among the specimens from the Dictyosponge colony at Cotton hill, the 

 great majority of which are very large though usually imperfect individuals 

 approaching Hydnoceras tuberosum, are a few fragments indicating a species of 

 this genus noteworthy in its size and the remarkable abundance of nodes. The 

 best of these specimens is that figured, which represents the upper part of a 

 large cup laterally compressed, as is the case with all the sponges at this local- 

 ity. Three transverse rows of nodes are shown on the exposed side, the lower 

 bearing eight, the middle one ten, and the upper, which appears to be the 

 apertui-al row, seven. All are small and low. The adventitious character of 

 many of these nodes is evident from a comparison of the different rows ; thus 

 one incipient node in the lower row is not represented in either of the others ; 

 similarly one node of the second row has no equivalent above or below, 

 while another is represented in the top row but not in the lower. The total 

 number of nodes in each upper row must have been not less than from 14 to 

 20, a feature which at once distinguishes the species. The more conspicuous 

 nodes in the vertical rows are connected by slightly elevated ridges or i-em- 

 nants of the prism-angles. The apertui'al width of the fragment is 180 mm., 

 its length 110 mm. 



Locality. In the lower Chemung group, one mile north of Avoca, 

 Steuben county, in association ^vith II. taberosiim, Arystidictya elegans, A. 

 nodifera, Hallodictya Cottoniana, etc. 



Hydnoceras Lutiieri, sp. nov. 



Plate viii, Figs. 7-10. 



Sponge very small and graceful, very gradually exjaanding, prism-faces 

 greatly obscured, growth usually regular. The rate of expansion from the 

 base to the first row of nodes is greater than elsewhere except about the 

 aperture. The nodes are well developed, with rounded extremities, and 

 are arranged in three or four horizontal rows which are separated by very 



