SpEcras OF TiiE Chkmuno Group. 103 



direction of the nodes of any pair is divergent and to such a degree as to 

 bring the summits of all the nodes to about the same interval. Each node is 

 laterally compressed and projected downward, so that each horizontal ro^v 

 presents a circlet of eight drooping, almost pendulous pouches. 



Reticulum rather fine-meshed. 



Dimensions. The species does not vary much in size. An average 

 example measures from apex to aperture, 135 mm.; its greatest width, across 

 the top row of nodes, is 60 mm.; the diameter of the body of the cup at the 

 subapertural constriction is 33 mm. 



The characters of this species are pronounced and readily recognized. Its 

 small size, subcylindrical body, elevated rows of double nodes, and the elon- 

 gate, I'ecurved form of the latter give it an expression not otherwise reproduced. 



Locality. The species occurs in hundreds at a locality known as Irish 

 hill, near the village of Bath, Steuben county. All the specimens that have 

 been examined from this spot (the Ii'IhIi hill coUymj) were found loose in the 

 fields and no systematic excavation has been made for them into the underlying 

 rocks. It also occurs, though not abundantly, in association with II. Batlienm 

 in the Jeiiks quarry cohny. A^vay from the immediate vicinity of liath the 

 fossil has not been observed. 



Hydnoceras Avoca, sp. nov. 



Plate ii, Figs. 1, 3; Plate ix, Fig. 3; Plate x, Pig. 1 ; Plate xi, Fio. 1. 



This form of Hydnoceras is rendered very distinct by its short, broadly 

 expanded nodes, very stout and wide at the base and Avith a subsemioval out- 

 line. The number of horizontal rows of nodes is usually four or five, includ- 

 ing the incipient row near the base. The horizontal constrictions are narrow 

 and deep, and the prismatic surface is obscurely retained. All the fonns of 

 this species observed indicate great size at maturity, as shown by the specimens 

 represented on Plates x and xi. That on the latter plate is the largest nodose 

 sponge yet seen and must have had a length when entire of not less than 625 

 mm., or about 2 feet. Reference has been made above to the occasional occur- 

 rence of passage forms from H. Batliense to this species, but the two represent 

 sharp extremes of variation in the form of the nodes. 



Locality. Hydnoceras Avoca is represented in the material under study 

 by perhaps a dozen specimens from the vicinity of Avoca, Steuben county. 

 Their precise position in the rocks has not yet been ascertained as the spec- 

 imens, most <jf them collected by the late Thomas Cotton of that village, 

 have been found loose. There is no satisfactory evidence of theii- occurrence 



