21G DlCTYOSPONGID^E. 



PLATE IX. 



HYDNOCERAS, Conrad. 



Page 95. 

 (See Plates II, III, IV, V, VI, VII, VIII, X, XI,Xir, XXXIII, XXXVI, XXXVII, XXXVIII, XXXIX, XLVI.) 



Hydnocebas Batiiense, sp. nov. 



Page 101. 

 (See Plates III, VIII.) 



Figure 1. A large, somewhat incomplete individual with six rows of strong 

 rounded nodes, showing some interesting peculiarities of develop- 

 ment. In the fourth row one node, instead of appearing at its proper 

 place, stands at the middle of the prism-face, and in the fifth row 

 the node of a different vertical series is wanting, while in the sixth 

 row, so far as it is preserved, there is but a single well defined node. 

 Chemung group. Jenks quarry^ Bath, New Yoi'h. 



Hydnocebas tubeeosum, Conrad, var. glossema, var. nov. 



Page 101. 

 (See Plate VII.) 



Figure 2. In this example there is a considerable area at the base, where an 

 incipient row of nodes is represented only by a series of broad swell- 

 ings at the prism-angles. Three horizontal rows are well developed, 

 and in the apertural region is evidence of another row of smaller 

 nodes. The two lower rows (not including the incipient row near 

 the base) have seven nodes, while that immediately above has eight, 

 the eighth vertical row appealing abiniptly, as shown in the figure. 

 The reticulation is sharply defined, but not finely divided. The sur- 

 face shows impressions of worm-like markings which, as elsewhere 

 suggested, may be the tube of some commensal annelid. 

 Chemung group. Southwestern New York (exact locality unlcncnun). 



Hydnocebas Avoca, sp. nov. 



Page 103. 

 (See Plates II, X, XI.) 



Figure 3. An imperfect example with three fully develojied horizontal rows 

 of large and short nodes with subsemicircular marginal outline, and 

 an inceptive basal row. The prismatic faces are obscured, except over 

 the basal region, and the horizontal constrictions are deep and naiTow. 

 Chemung group. Near Avoca, New Yo)-k. 



