102 DlCTYOSPONGID^ 



nodes in the mature individual, there being usually five or six well developed 

 rows, and also by the size of the nodes themselves, which are strongly elevated, 

 compressed laterally and have an elongated semielliptical or oval outline. 

 The height of these nodes is often equal to one-third and sometimes even to 

 one-half the diameter of the body of the cup. Their summits are almost 

 invariably wanting, indicating a tufted reticulum at these points. The sub- 

 prismatic surface of the cup is less clearly retained than in II. tuheroHum, and 

 the rate of expansion and the concavity of the horizontal constriction is less 

 pronounced. 



Sponges with these characters well defined have thus far been found 

 largely localized in the neighborhood of Bath, N. Y., where the specific traits 

 described are maintained by multitudes of individuals. Away from this 

 locality there seems to be a progressive modification in the form of the nodes, 

 which lose their elongate tapering outline and gradually approach their very 

 distinct expression in the species, II. Avoca, The predominance of these two 

 forms under different geographical conditions justifies their description as 

 distinct species notwithstanding the desultory occurrence of passage forms in 

 other localities. 



Locality. Ilydnoceras Bathense is exceedingly abundant at the Jenks 

 quarry, one mile southeast of the village of Bath, Steuben county, where it 

 occurs in thin shaly layers between two heavy compact beds of greenish 

 sandstone, whose fine grain has preserved the lines of the reticulum with much 

 distinctness. In association with it at this locality occurs an occasional speci- 

 men of H. hotrcedema. Outside of the Jen1c8 quarry colony, typical specimens 

 have not been found. 



Hydnoceras botrcedema, sp. nov. 



Plate ii, Fig. 4. 

 Sponge rather small, slender, very gently expanding ; with four horizontal 

 rows of very strong digitiform nodes separated by deep horizontal con- 

 strictions. Over these concave areas the surface of the cup is totally without 

 trace of the prismatic surface shown in allied species, and when uncom- 

 pressed is circular in section. The body of the cup, were the nodes removed, 

 would be very narrow and quite cylindrical. The nodes are arranged in eight 

 vertical rows, which are, in reality, four double rows, and any two adjacent 

 meml>ei-s of these double rows arise from a common and thickened base. 

 Nearly one-half the height of these nodes from the bottom of the horizontal 

 constriction upwards, is below the level of the concavity dividing their prox- 

 imal surfaces. Thus each pair of nodes stands upon an elevated base. The 



