Species of tjie Portaok Group. ^^^) 



PRISMODICTYA, gen. nov. 



(For description see page 79.) 



Prismodictya paljja, sp. nov. 



Platk XXXIII, Fio. 2. 



The original specimen of this species indicates a small, elongate cup, 

 expanding rather rapidly and attaining full width at al)Out one-third of its 

 length from the base. Its median width is about one-fourth of its entire 

 length and its aperture is somewhat contracted. 



The surface shows that the prism faces are distinctly developed and these 

 are crossed by two or three low horizontal ridges making vertically elongate 

 rectangles with the prism-angles and at their intersections are low, very small 

 nodes. 



Reticulum very fine. 



The single example observed has a length of 50 mm., a median width of 

 14 mm. and an apertural width of 10 mm. 



Locality. In the Portage sandstones ; second falls of the Tannery gully, 

 Naples, N. Y. (Collected by D. D. Luther.) 



HYDNOCERAS, Conrad. 

 (For description see page 95.) 



Hydnocebas legatum, sp. nov. 



PLA.TE XXXIII, Fios. 5, 6. 



Recent explorations have shown the presence in the Portage beds of a 

 species which appears to be closely allied to typical forms of II. tnberomnn, 

 Conrad, of the Chemung sandstones. None of the material thus far collected, 

 though from two localities, is of good quality, but enough is retained by the 

 fragments gathered to show the presence of from four to six transverse rows 

 of nodes which, over the lower portion of the sponge, are moderately strong 

 and are separated by deep constrictions which bear little, if any, evidence of 

 prismatic division. A fragment of a large individual has these nodes large, 

 robust and blunt, similar to those in the gigantic fonu, II. Avoca, of the 

 Chemung. (See Plate xi). 



The reticulum is finely divided, rather more so than is usual in II. tube- 

 rosum. Probably additional differentiating features will appear when this 

 Portage fossil becomes better known. For the present it seems wise to recog- 

 nize the fossil by a distinct appellation, its specific value being tentative. 



