92 DicTYospoKoiD.?;. 



Locality. In the upper beds of tlie Chemung group, at Randolph, 

 Cattaraugus county, N. Y. 



GONGYLOSPONCtIA, gen. nov. 

 Elongate, subprismatic sponges, with irregular protuberances or nodes 

 developed on the prism-faces in single alternate or opposite vertical rows. 

 Type, Gongylospongia Mwrsld, sp. nov. 



GoNGYLOSPONGIA MaRSIII, Sp. nOV. 



Sponge approaching Prismodicty a in general aspect, the prism-faces being 

 clearly manifested throughout the length of the skeleton. The expansion 

 from the base upward is gradual and is greatest at about two-thirds of the 

 length from the point of attachment. 



Near the base, protuberances appear on each prism-face in a vertical row. 

 These protuberances are at first low and irregular lumps, separated from each 

 other by more or less longitudinal depressions. With increase in the size of 

 the sponge, the protuberances become more prominent and may show several 

 points or apices, while the separating depressions are much deeper. When at 

 full size the surface of the protuberances may carry several small and irregular 

 concavities. 



On adjacent prism-faces these nodes seem to correspond for the most part 

 in position, but there are noticeable exceptions in which a depression in one row 

 lies against a node of another. Moreover there is a frequent difference in the 

 size and number of these projections in the various rows. Irregularity in all 

 traits is their leading cliaracteiistic. 



The prism-angles are pretty sharply developed between these rows of 

 nodes and on some of the faces the vertical angles of the second order are 

 seen to traverse the nodes. 



After the maturity and full size of the sponge has been attained, the 

 node-like irregularities rapidly disappear and all the later portion of the 

 sponge is free of them. Over the apertural region, hence, the prismatic and 

 primitive form of the sponge is stiikingly manifested. 



Keticidimi as in Prismodictya. 



Dirnenskms. The single specimen found of this interesting species is 

 repi-esented in the accompanying illustrations. Its length is 190 mm.; greatest 

 width (under some compi-ession) 70 mm., and apertural width 55 mm. 



Locality. In the Chemung beds at AVellsville, N. Y. (Collection of 

 E. B. Hall.) Named for Professor O. C. Marsh, of New Haven, Conn. 



