250 I>lCl'Y<>SI><)N(JII)iK, 



PLATE XXIX. 



HYPHANT^NIA, Vanuxem. 



Pago 137. 

 (See Plates XXVIII »nd XLV.) 



IIypiiant^nia Ciiemungensis, Vanuxem. 



Page 139. 

 (See Plates XXVIH and XLV.) 



Figure 1. A fragment of a specimen whose entire diameter is probably 

 represented. This appears to be a mould from an impression of 

 the exterior, shows the expanding saucer-shaped form of the sponge, 

 the raj)id increase in the width of the radial bands, also their elevated 

 margins and the open quadrangular interspaces made by the inter- 

 section of the two series of bands. The center of the specimen 

 as Avell as that represented in figure 1 on the preceding plate lacks 

 definition and lends probability to the inference that there was a 

 tuft of basal spicules at this point. 

 Chemung group. Near Owego, Tioga county, New York. 



