Spkciks of the Cukmuno Group. 91 



Prismodictya Conbadi, Ilall (sp.). 



Plate xviii, Fio. 4 ; Platk xix, Kio8. 5, 6. 



1863. Dkiyophyton Conradi, Hall. Sixteenth Ann. Kept. N. Y. State Cab. 



Nat. Hist., p. 89, pi. v, fig. 2, pi. v a, fig. 2. 

 1884. T)icty<q)hyton Conradi, Hall. Thirty-fifth Ann. Kept. N. Y. State 



Mas. Nat. Hist., p. 471, pi. (17) 18, figs. 8, 4, 4a. 

 1882. Dictyophyton Conradi, Hall. Notes on the Family Dictyospongidse, 



pi. 17, figs. 3, 4, 4a. 



Sponge obconical, slightly arcuate toward the base; the original specimen 

 is somewhat compressed laterally, sharply prismatic, the eight j)ri8ra-face8 

 being without evidence of median longitudinal ridges, with obscurely concave 

 surfaces and brondly elevated margins. Toward the upper extremity are a 

 few nodiform protuberances produced by the depression and elevation of the 

 surfaces between the prism-angles. These nodes are low, evenly rounded and 

 alternate in position on adjoining faces, presenting thus to some degree 

 the aspect of the nodiform sui-face in the genus Physospongia. The speci- 

 men unfortunately terminates soon after the appearance of these nodes. 

 The prism-angles are not modified by this configuratif)n of the faces. On 

 one side of the specimen, however, at something less than one-half its length 

 from the apex, are two or three lower elevations in a transverse line on the 

 prism-angles. 



lidic/fdum. Each prism-angle bears the impression of a strong vertical 

 strand of spicules, which is crossed at subecpial intervals by similarly strong 

 horizontal bands. This interval is about 5 mm. and is maintained from base 

 to top without material increase or diminution. Where these intersect the 

 primary bands, there are slight cavities or minute pits such as are more dis- 

 tinctly seen in specimens of P.prismatica, and which probably indicate the 

 existence of small spicular tufts at these points of intersection. The absence 

 of prominent vertical bands upon the surface of the prism-faces, gives to the 

 primary division of the reticulum the aspect of a series of transverse and flat 

 annular bands. Considering the primary quadrules to be about 5 mm. square, 

 it is possible to trace on some parts of the specimen a division of the reticulum 

 to the sixth degree. 



Dimendons. The length of the original specimen is 1 30 mm. ; its diam. 

 eter at the apical end, 5 mm. ; at one-half its length its major and minor diam- 

 eters are 38 and 23 mm., while at the upper extremity these are 44 and 22 mm. 



